da'wah (Islamic invitation)

وَمَنْ أَحْسَنُ قَوْلًا مِّمَّن دَعَآ إِلَى ٱللَّهِ وَعَمِلَ صَـٰلِحًا وَقَالَ إِنَّنِى مِنَ ٱلْمُسْلِمِينَ

And who is better in speech than one who invites to Allāh and does righteousness and says, "Indeed, I am of the Muslims."