A role model or exemplar.
One confused human being.
It depends what religion they are. If he is preaching Judaism he is probably a rabbi Catholics are priests and Protestants are ministers.
Jews
A person who leads a cult is often referred to as a cult leader. They typically have a charismatic personality and use manipulation tactics to gain control over their followers.
The religion is Judaism. A person who follows Judaism is Jewish.
Confucianism: The Analects Judaism: Tanakh/Torah
Initiator
People who believe in Judaism are called Jews.
Any male 13 years old or older (Orthodox) or any male 13 years old or female 12 years old or older (all other Jewish groups) can lead religious services in Judaism. This being said, in more organised formats, the leadership of religious services in Judaism is a joint effort between rabbis and cantors.
Judaism.
Cold calling is when you have no leads for making calls and you have to just call out of a phone book. Leads are names with phone numbers that are given to you so you do not have to look them up. It is much easier to get leads.