This is not true. However the reward is great.

A friend of mine told me that if a person gives Da’wah to non-Muslims and if even a single person accepts Islam and start practicing it, then the person who gave Dawah will get guaranteed Jannah. He says that the reward for this act is assured and guaranteed Jannah and there is also a hadith for it. Please let me know if he is right and does it guarantee a secure place in Jannah?

Inviting others to Islam |