Albert Barnes Commentary Matthew 3:10

"And even now the axe lieth at the root of the trees: every tree therefore that bringeth not forth good fruit is hewn down, and cast into the fire." — Matthew 3:10 (ASV)

The axe is laid unto the root of the trees. Laying the axe at the root of a tree is intended to denote that the tree is to be cut down. It was not merely to be trimmed, to be cut about the limbs, but the very tree itself was to be struck.

That is, a searching, trying kind of preaching has begun. A kingdom of justice is to be set up. Principles and conduct are to be investigated. No art, no pretenses, are to be successful. People are to be tried by their lives, not by birth or profession. Those who are not found to bear this test are to be rejected.

The very root will feel the blow, and the fruitless tree will fall. This is a beautiful and very striking figure of speech, and a very direct threat of future wrath. John regarded them as making a fine and promising profession, as trees do in blossom. But he also told them that they should bear fruit as well as flowers. Their professions of repentance were not enough. They should show by a holy life that their profession was genuine.