# because he is a prophet

Here "he" does not refer to the person who is welcoming. It refers to the person being welcomed.

# a prophet's reward

This refers to the reward that God gives the prophet, not to the reward that a prophet gives to another person.

# he is a righteous man

Here "he" does not refer to the person who is welcoming. It refers to the person being welcomed.

# a righteous man's reward

This refers to the reward God gives to a righteous person, not a reward that a righteous person gives to another person.