'Root' in the Bible

The axe is already laid at the root of the trees; therefore every tree that does not bear good fruit is cut down and thrown into the fire.

But when the sun had risen, they were scorched; and because they had no root, they withered away.

yet he has no firm root in himself, but is only temporary, and when affliction or persecution arises because of the word, immediately he falls away.

But he *said, ‘No; for while you are gathering up the tares, you may uproot the wheat with them.