What does Matthew 23:15 mean?

These are some of Christ' harshest words against the religious teachers of ancient Israel. This is the second of seven statements of judgment made against them by the Son of God. The opening pattern is the same, declaring their impending judgment and labelling them as pretenders: as hypocrites.

The reference to extensive travel might be exaggeration for effect—hyperbole—rather than an indication that the Pharisees went to foreign territory to seek converts. Scribes and Pharisees made extensive efforts to create "proselytes." These are converts from one religious conviction to another. Some scholars and historians understand this to be a literal form of missionary work in which the Pharisees attempted to convert non-Jews to religious Judaism.

Some interpreters believe Jesus is referring to efforts by the scribes and Pharisees to win over current believers in Judaism. These might have been Gentiles who already believed in the God of Israel. The goal would have been to convince such people of their narrow views of the law, along with their teachings about the extra rules and regulations they required.

In either case, Jesus does not condemn the effort to win converts. He condemns what they are being won to: a belief system built around human regulations and a rejection of Jesus as the Messiah. These hypocritical religious leaders were redirecting people onto a path leading to hell, rather than to God and heaven. Those converted were likely to follow the wrong teachings of the Pharisees even more closely than the Pharisees did themselves!