How does the call bear fruit?

The fruits of da'wah (inviting to Islam) come from two directions: the da'i (caller) fulfilling his responsibility of da'wah and thereby clearing himself of blame, and the da'wah influencing the invitees by the da'i adhering to the principles of da'wah and the methodology of the prophets. The da'i must be patient and not rush for the fruits, because the guidance of hearts is in the hand of Allah. The da'i's mission is to perform the da'wah in the most complete way, in accordance with the Almighty's saying: "Indeed, [O Muhammad], you do not guide whom you like, but Allah guides whom He wills. And He is most knowing of the [rightly] guided."