Jesus told his followers:

15 “Beware of false prophets, who come to you in sheep’s clothing, but inwardly are ravening wolves. 16 By their fruits you will know them. Do you gather grapes from thorns, or figs from thistles? 17 Even so, every good tree produces good fruit; but the corrupt tree produces evil fruit. 18 A good tree can’t produce evil fruit, neither can a corrupt tree produce good fruit. 19 Every tree that doesn’t grow good fruit is cut down, and thrown into the fire. 20 Therefore by their fruits you will know them."

Matthew 7:15-20 - World English Bible

At the beginning of Matthew 7, Jesus warned his disciples about judging others; now, he assumed they would size up those who claim a mantle of leadership. The difference, of course, was the social peaking order. The disciple did not judge an equal or one below them, but the person who strove for authority. A disciple had a responsibility to measure the worth of a leader, for, by definition, a follower aligned himself with the values and direction of the one above him. Was it worth the energy or effort to be part of a leader's group or social circle? That was the question the Lord implicitly asked his audience.

Jesus gave a pragmatic answer in an agricultural analogy. Don't look to the person's ideas but to the results of their behavior (fruit). Product trumps ideology. A leader could have a smooth delivery, but if their actions were shady or their intent was self-serving, beware! "By their fruits you will know them."

Which leaders do you admire? Why? Which ones have disappointed you? Why? What sort of leader are you?