Da’wah is a communal obligation upon the nation, whether they accept or not.
{قُلْ هَـٰذِهِۦ سَبِيلِىٓ أَدْعُوٓا۟ إِلَى ٱللَّهِ ۚ عَلَىٰ بَصِيرَةٍ أَنَا۠ وَمَنِ ٱتَّبَعَنِى}
“Say, "This is my way; I invite to Allaah with insight, I and those who follow me…” (Yoosuf 108)
Da’wah is a communal obligation upon the nation, and it is necessary to carry it out. Looking at the other party as to whether they accept or not is another issue. Regarding this is Allaah’s Words,
{سَوَآءٌ عَلَيْهِمْ ءَأَنذَرْتَهُمْ أَمْ لَمْ تُنذِرْهُمْ لَا يُؤْمِنُون}
“... it is all the same for them whether you warn them or do not warn them-they will not believe.” (Al-Baqarah 6 and Yaaseen 10)
This aayah does not mean we do not warn because it is all the same for us whether you warn them or do not warn them. No! No scholar has said this. Those who will not believe are the ones who have been decreed to do so, but how do we know that this person who is being invited has been decreed to not believe? Invite.
“Surely, if Allaah guides through you one man, this is better for you than red camels.”
When the last aayah was revealed, did the Messenger stay at home? Did he say, ‘They will not believe so I will stay at home.’ He was ordered to convey the Message and his nation is ordered to give da’wah. Even an obstinate person is given da’wah in a manner which is best, and the manner is change appropriately for them, so that they may take heed. Many people were resistant at first at the time of the Prophet , then they accepted the invitation. ‘Umar ibn Al-Khatt-ttaab only accepted Islaam after some years, and, likewise, did many companions, and Allaah made them a great benefit.
“Surely, if Allaah guides through you one man, this is better for you than red camels.”