How shall not the ministration of the Spirit - This is an argument from the less to the greater. Several things in it are worthy of notice:
(1) The proper contrast to the "ministration of death" 2-Corinthians 3:7, would have been 'ministration of life.' But Paul chose rather to call it the 'ministration of the spirit;' as the source of life; or as conferring higher dignity on the gospel than to have called it simply the ministration of life.
(2) by the "Spirit" here is manifestly meant the Holy Spirit; and the whole phrase denotes the gospel, or the preaching of the gospel, by which eminently the Holy Spirit is imparted.
(3) it is the high honor of the gospel ministry, that it is the means by which the Holy Spirit is imparted to human beings. It is designed to secure the salvation of people by his agency; and it is through the ministry that the Holy Spirit is imparted, the heart renewed, and the soul saved. The work of the ministry is, therefore, the most important and honorable in which man can engage.
Be rather glorious -
(1) Because that of Moses tended to death; this to life.
(2) because that was engraved on stone; this is engraved on the heart.
(3) because that was the mere giving of a law; this is connected with the renovating influences of the Holy Spirit.
(4) because that was soon to pass away. All the magnificence of the scene was soon to vanish. But this is to remain. Its influence and effect are to he everlasting. It is to stretch into eternity; and its main glory is to be witnessed in souls renewed and saved; and amidst the splendors of heaven. "The work of the Spirit of God on the heart of a rational being, is much more important than any dead characters which can be engraved on insensible stones" - Doddridge.

The ministration of the Spirit - The Gospel dispensation, which gives the true spiritual sense of the law.
Be rather glorious? - Forasmuch as the thing signified is of infinitely more consequence than that by which it is signified. The Thing bread will preserve a man alive; the Word bread can give life to nothing.

How shall not the (i) ministration of the spirit be rather glorious?
(i) By which God offers, indeed, and gives the Spirit, not as a dead thing, but a living Spirit, working life.

How shall not the ministration of the Spirit,.... By "the ministration of the Spirit", is meant the Gospel; so called not only because it ministers spiritual things, as peace, pardon, righteousness and salvation, spiritual joy and comfort, and even spiritual life; but because it ministers the Spirit of God himself, by whom it is not only dictated, and by him at first confirmed, and who qualities persons for the preaching of it; but by it he conveys himself into the hearts of men, and makes it powerful for illumination, consolation, edification, and an increase of every grace; and therefore must be rather glorious, or much more glorious than the law, the ministration of death.

be rather glorious--literally, "be rather (that is, still more, invested) in glory." "Shall be," that is, shall be found to be in part now, but fully when the glory of Christ and His saints shall be revealed.

The ministration of the Spirit - That is, the Christian dispensation.