﴿ ذَٰلِكَ بِأَنَّ ٱللَّهَ مَوْلَى ٱلَّذِينَ ءَامَنُوا۟ وَأَنَّ ٱلْكَٰفِرِينَ لَا مَوْلَىٰ لَهُمْ ﴾

“This, because God is the Protector of all who have attained to faith, whereas they who deny the truth have no protector.”

(That) i.e. helping the believers (is because Allah is patron) helper (of those who believe) in Muhammad (pbuh) and the Qur'an, (and because the disbelievers) of Mecca (have no patron) have no helper.