John 13:29

For some of them thought
This was the thought of some of the disciples, it may be of all of them but John;

because Judas had the bag:
which was for the common supply of Christ and his disciples, and for the relief of the poor; (See Gill on John 12:6).

That Jesus had said unto him, buy those things that we have need of
against the feast;
the feast of the passover, which was to be two days after; and shows, that this was not the passover which Christ now ate with his disciples:

or that he should give something to the poor;
for whom Christ cared, and had a hearty concern, and for whom Judas had very little, notwithstanding his high pretensions.