How were the Buddha, Jesus, and Muhammad similar?

Something of significance in a previous life (not necessarily someone) = Buddha

Prov. 30:4 "Who has ascended into heaven, or descended? Who has gathered the wind in His fists? = Jesus

Like Jesus and Buddha, Mohammed had inherited no priestly authority but became a lay preacher ... Mohammed, for his part, made almsgiving a central religious duty as did Jesus.

Explanation:

Like Jesus and Buddha, Mohammed had inherited no priestly authority but became a lay preacher ... Mohammed, for his part, made almsgiving a central religious duty as did Jesus.