And they reasoned among themselves, saying, It is because we have taken no bread.

But they thought within themselves, saying: Because we have taken no bread.

and they were reasoning in themselves, saying, 'Because we took no loaves.'

they reasoned among themselves, saying, "It is because we have not brought any bread."

And they were reasoning among themselves, saying, We took no bread.

But they were thinking within themselves, saying, "It is because we have not brought bread."

But the disciples began talking among themselves about their having brought no bread.

They reasoned - For, as Lightfoot observes, the term leaven was very rarely used among the Jews to signify doctrine, and therefore the disciples did not immediately apprehend his meaning. In what a lamentable state of blindness is the human mind? Bodily wants are perceived with the utmost readiness, and a supply is sought with all speed. But the necessities of the soul are rarely discovered, though they are more pressing than those of the body, and the supply of them of infinitely more importance.

Either what should be the meaning of this caution of Christ's, and upon what account he should say this to them; or they were anxiously concerned what they should do for provision:
saying, because we have taken no bread; for the phrase, "it is", is a supplement, and is not in the original text, which confines the sense to the first way of interpretation; the words may be read without it, and confirms the other sense, and which receives strength from what follows.

It is because we took no bread. The thoughts of the disciples were so fixed upon their failure to supply bread that they thought the remark about leaven contained a rebuke. The Lord reminds them of his creative power, and how it has been put forth.

They reasoned among themselves - What must we do then for bread, since we have taken no bread with us?