Da'i, Who Calls Others to Allah

Hasan Al Basri (rahimahullah) recited the verse,
‘Whose speech can be better than the one who calls to Allah, who performs righteous deeds and says, ‘I am from the Muslims’ (Surah Fussilat, Verse: 33) and then said:
“This person [referred to in the above verse] is the beloved of Allah, the friend of Allah, the chosen one of Allah, the most beloved of all those on earth to Allah. He has answered Allah’s call, and has invited the people [to respond to] what he has responded. He has done good in answering Allah and has declared that he is from among the Muslims, [and therefore he is] the vicegerent of Allah”
[Tafsir Abdur Razzaq; Refer: Tafsir Ibn Kathir, Surah Fussilat, Verse: 33 and Tafsir Tabari]