The copulative and should be resolved into the disjunctive particle but, because David employs language full of confidence, in opposition to the hardihood and profane scoffings of his enemies,. and testifies that whatever they may say, he would nevertheless rely upon the word of God. It besides appears that he had previously entertained an assured hope of deliverance, from the circumstance of his here making no mention of his present calamity as a chastisement inflicted upon him by the hand of God; but rather depending upon the divine aid, he courageously encounters his enemies, who were carrying on an ungodly and wicked war against him, seeing they intended to depose a true and lawful king from his throne. In short, having acknowledged his sin before, he now takes into consideration only the merits of the present cause. And thus it becomes the servants of God to act when molested by the wicked. Having mourned over their own sins, and humbly betaken themselves to the mercy of God, they ought to keep their eyes fixed on the obvious and immediate cause of their afflictions, that they may entertain no doubt of the help of God when undeservedly subjected to evil treatment. Especially when, by their being evil entreated, the truth of God is opposed, they ought to be greatly encouraged, and glory in the assurance that God without doubt will maintain the truth of his own promises against such perfidious and abandoned characters. Had it been otherwise with David, he might seem to have claimed these things to himself groundlessly, seeing he had deprived himself of the approbation and help of God by offending him. But being persuaded that he was not utterly cut off from the favor of God, and that God's choice of him to be king remained unchanged, he encourages himself to hope for a favorable issue to his present trials. And, in the first place, by comparing God to a shield, he means that he was defended by his power. Hence also he concludes, that God was his glory, because he would be the maintainer and defender of the royal dignity which he had been pleased to confer upon him. And, on this account, he became so bold that he declares he would walk with unabashed brow.

But thou, O Lord, art a shield for me - Not only in these dangers, but in all dangers. The declaration here has a general form, as if he could trust in him at all times. It shows what his feelings were on the occasion here referred to, when dangers stood thick around him, and what his feelings habitually were in times of peril. The shield was a well-known part of ancient armor, of use, according to the ancient modes of warfare, when swords, and spears, and arrows were employed, but of use only then, since they would constitute no defense against a musket or cannonball. They were usually made of tough and thick hides, fastened to a rim, and so attached to the left arm that they could be readily thrown before the body when attacked, or so that, as they were usually held, the vital parts of the body would be protected. See the notes at Ephesians 6:14-16. From this use of the shield it was natural to speak of God as the "shield," or the "Protector" of his people - an appellation which is often given to him in the Scriptures (Genesis 15:1; Deuteronomy 33:29; 2-Samuel 22:3; Psalm 28:7; Psalm 119:114; Psalm 144:2; Psalm 33:20; Psalm 84:11; Proverbs 30:5.
My glory - My honor, or the source of my honor. That is, he bestows upon me all the honor that I have, and it is my glory that I may put my trust in him. I regard it as an honor to be permitted, in times of danger and trouble, to rely on him - a sentiment in which every true child of God will unite.
And the lifter up of my head - The head, in time of trouble and sorrow is naturally bowed down, as if overpowered with the weight of affliction. See Psalm 35:14 : "I bowed down heavily as one that mourneth for his mother;" Psalm 38:6 : "I am bowed down greatly; I go mourning all the day." Compare Psalm 42:5; Psalm 44:25; Psalm 57:6; John 19:30. To lift up the head, therefore, or to raise one up, is to relieve his distresses, or to take away his troubles. Such a helper, David says, he had always found God to be, and he looks to him as one who is able to help him still. That is, he feels that God can so entirely take away his present griefs as to reinstate him in his former happy and honorable condition.

Thou, O Lord art a shield - As a shield covers and defends the body from the strokes of an adversary, so wilt thou cover and defend me from them that rise up against me.
The lifter up of mine head - Thou wilt restore me to the state from which my enemies have cast me down. This is the meaning of the phrase; and this he speaks prophetically. He was satisfied that the deliverance would take place, hence his confidence in prayer; so that we find him, with comparative unconcern, laying himself down in his bed, expecting the sure protection of the Almighty.

But thou, O Lord, art a shield for me,.... Or "about me" (a) protecting and defending me. David was a military man, and often alludes to military affairs; and borrows words from thence, expressive of his great security from the Lord; see Psalm 18:2. So Jehovah the Father was a shield to Christ, in his infancy, from Herod's rage and fury; and afterwards from the insults of the Pharisees, and their attempts to take away his life before the time; and in his sufferings and death, so as that his faith and confidence in him were kept up, and he got the victory over sin, Satan, and the world; see Psalm 22:9. And the Lord is a shield unto all his people, Genesis 15:1. They are kept by his power, and encompassed about with his favour, as with a shield; his veracity and his faithfulness in his promises, and his truth, are their shield and buckler: and especially his Son, the Lord Jesus Christ, is the shield which faith makes use of, particularly his blood and righteousness, and salvation by him; which it holds up, and defends itself with, against the charges of the law, the accusations of conscience, and the temptations of Satan; and which are a security from the justice of God, and wrath to come;
my glory; who took David from the sheepfold, and made him king over Israel, and raised him to all the glory he had enjoyed; and in whom he gloried as his covenant God, and of whom he made his boast; and not of his strength, valour, wisdom, riches, and honour. So God the Father is the glory of Christ, the glorifier of him, by supporting him under his sufferings, raising him from the dead, and setting him at his own right hand, where he is crowned with glory and honour: he is the glory of his people, in whom they glory, and by whom they are called to eternal glory; and who will give it to them, and reveal it in them, even an eternal weight of it, which the sufferings of this life are not worthy to be compared unto;
and the lifter up mine head; such as the helmet is: the Lord was lifter up of David's head when he brought him to the throne, and afterwards gave him victory over his enemies; for so the phrase of lifting up the head signifies; see 2-Kings 25:27. And he was the lifter up of Christ's head when he raised him from the dead; and exalted him, both with and at his right hand, to be a Prince and a Saviour, and gave him a name above every name. And he is the lifter up of the heads of his people in conversion, when he raises them from a low estate, and sets them among princes to inherit the throne of glory; and when he gives them comfort, peace, and joy, which causes them to lift up their heads; whereas in sorrow, and mourning, and distress, the head is bowed down like a bulrush, Isaiah 58:5; and when he gives them boldness and confidence, as at the throne of grace now, through the sprinkling of the blood of Christ upon them; so at the bar of judgment hereafter, through the righteousness of Christ put upon them, as that they shall not be ashamed nor confounded; see Luke 21:28; and he will be the lifter up of their heads in the resurrection morn, and when they shall appear with Christ in glory.
(a) "circa me", Junius & Tremellius, Piscator, Muis, Ainsworth, Cocceius, Michaelis.

But--literally, "and" (Psalm 2:6). He repels the reproach by avowing his continued trust.
shield--a favorite and often-used figure for protection.
my glory--its source.
lifter up of mine head--one who raises me from despondency.

(Hebrews.: 3:4-5) But cleansed by penitence he stands in a totally different relationship to God and God to him from that which men suppose. Every hour he has reason to fear some overwhelming attack but Jahve is the shield which covers him behind and before (בּעד constr. of בּעד = Arab. ba‛da, prop. pone, post). His kingdom is taken from him, but Jahve is his glory. With covered head and dejected countenance he ascended the Mount of Olives (2-Samuel 15:30), but Jahve is the "lifter up of his head," inasmuch as He comforts and helps him. The primary passage of this believing utterance "God is a shield" is Genesis 15:1 (cf. Deuteronomy 33:29). Very far from praying in vain, he is assured, that when he prays his prayer will be heard and answered. The rendering "I cried and He answered me" is erroneous here where אקרא does not stand in an historical connection. The future of sequence does not require it, as is evident from Psalm 55:17. (comp. on Psalm 120:1); it is only an expression of confidence in the answer on God's part, which will follow his prayer. In constructions like קולי אקרא, Hitzig and Hupfeld regard קולי as the narrower subject-notion beside the more general one (as Psalm 44:3; Psalm 69:11; 83:19): my voice - I cried; but the position of the words is not favourable to this in the passage before us and in Psalm 17:10; Psalm 27:7; Psalm 57:5; Psalm 66:17; Psalm 142:2, Isaiah 36:9, though it may be in Psalm 69:11; Psalm 108:2. According to Ew. 281, c, קולי is an accusative of more precise definition, as without doubt in Isaiah 10:30 cf. Psalm 60:7; Psalm 17:13.; the cry is thereby described as a loud cry.
(Note: Bttcher, Collectanea pp. 166f., also adopts the view, that נפשׁי, פּי, קולי are each appositum vicarium subjecti and therefore nomin. in such passages. But 1) the fact that את never stands beside them is explained by the consideration that it is not suited to an adverbial collateral definition. And 2) that elsewhere the same notions appear as direct subjects, just as 3) that elsewhere they alternate with the verbal subject-notion in the parallel member of the verse (Psalm 130:5; Proverbs 8:4) - these last two admit of no inference. The controverted question of the syntax is, moreover, an old one and has been treated of at length by Kimchi in his Book of Roots s. r. אוה.)
To this cry, as ויּענני as being a pure mood of sequence implies, succeeds the answer, or, which better corresponds to the original meaning of ענה (comp. Arab. ‛nn, to meet, stand opposite) reply;
(Note: Vid., Redslob in his treatise: Die Integritat der Stelle Hosea. vii. 4-10 in Frage gestellt S. 7.)
and it comes from the place whither it was directed: מהר קדשוּ. He had removed the ark from Kirjath Jeraim to Zion. He had not taken it with him when he left Jerusalem and fled before Absolom, 2-Samuel 15:25. He was therefore separated by a hostile power from the resting-place of the divine presence. But his prayer urged its way on to the cherubim-throne; and to the answer of Him who is enthroned there, there is no separating barrier of space or created things.

A shield - My defence. My glory - Thou hast formerly given, and wilt farther give occasion of glorying in thy power and favour. Lifter up - Thou wilt restore me to my former power and dignity.