Ibn `Abbas said, "Whoever thinks that Allah will not help Muhammad ﷺ in this world and the Hereafter, let him stretch out a rope
إِلَى السَّمَآءِ
(to the ceiling) to the ceiling in his house,
ثُمَّ لْيَقْطَعْ
(and let him strangle himself.) let him hang himself with it." This was also the view of Mujahid, `Ikrimah, `Ata', Abu Al-Jawza', Qatadah and others. The meaning is: whoever thinks that Allah will not support Muhammad ﷺ and His Book and His Religion, let him go and kill himself if it annoys him so much. For Allah will most certainly help and support him. Allah says:
إِنَّا لَنَنصُرُ رُسُلَنَا وَالَّذِينَ ءَامَنُواْ فِى الْحَيَوةِ الدُّنْيَا وَيَوْمَ يَقُومُ الاٌّشْهَـدُ
(Verily, We will indeed make victorious Our Messengers and those who believe in this world's life and on the Day when the witnesses will stand forth.) 40:51. Allah says here:
فَلْيَنْظُرْ هَلْ يُذْهِبَنَّ كَيْدُهُ مَا يَغِيظُ
(Then let him see whether his plan will remove that whereat he rages!) As-Suddi said, "Meaning, in the case of Muhammad " `Ata' Al-Khurasani said, "Let him see whether that will cure the rage he feels in his heart."
وَكَذلِكَ أَنزَلْنَـهُ
(Thus have We sent it down) the Qur'an.
ءَايَـتٌ بَيِّنَـتٌ
(as clear Ayat,) clear in its wording and its meaning, evidence from Allah to mankind.
وَأَنَّ اللَّهَ يَهْدِى مَن يُرِيدُ
(and surely, Allah guides whom He wills.) He sends astray whomsoever He wills and He guides whomsoever He wills, and He has complete wisdom and definitive proof in doing so.
لاَ يُسْأَلُ عَمَّا يَفْعَلُ وَهُمْ يُسْـَلُونَ
(He cannot be questioned about what He does, while they will be questioned.) 21:23. Because of His wisdom, mercy, justice, knowledge, dominion and might, no one can overturn His ruling, and He is swift in bringing to account.