Luke 7:29

And all the people that heard him
Either Christ saying these things in commendation of John, and gave their assent to them, and showed their approbation of them, having been baptized by him; or rather, the people that had heard John preach the doctrines of repentance and faith, and of baptism; for these words seem rather to be the words of Christ, relating the success of John's ministry among different persons:

and the publicans justified God;
even those wicked men, who were before profligate and abandoned sinners, when they came under John's ministry, were so wrought upon by the power and grace of God through it, that they approved of, and applauded the wisdom, goodness, and grace of God, in sending such a prophet as John; in qualifying him in the manner he did, and giving in him a commission to preach such doctrines, and administer such an ordinance as he did: and this their approbation of the divine conduct, and their thankfulness for the same, they testified by their

being baptized with the baptism of John;
they expressed their sentiments by their obedience; they declared it was right in God to institute such an ordinance, and for John to administer it; and that it became them to submit to it, as a part of righteousness to be fulfilled; they hereby signified, that they thought that it was agreeable to the nature of God, who is holy, just, and good, suitable to the Gospel dispensation, and very fit and proper for them.