Qur'an 3:81

وَإِذْ أَخَذَ ٱللَّهُ مِيثَـٰقَ ٱلنَّبِيِّـۧنَ لَمَآ ءَاتَيْتُكُم مِّن كِتَـٰبٍ وَحِكْمَةٍ ثُمَّ جَآءَكُمْ رَسُولٌ مُّصَدِّقٌ لِّمَا مَعَكُمْ لَتُؤْمِنُنَّ بِهِۦ وَلَتَنصُرُنَّهُۥ ۚ قَالَ ءَأَقْرَرْتُمْ وَأَخَذْتُمْ عَلَىٰ ذَٰلِكُمْ إِصْرِى ۖ قَالُوٓا۟ أَقْرَرْنَا ۚ قَالَ فَٱشْهَدُوا۟ وَأَنَا۠ مَعَكُم مِّنَ ٱلشَّـٰهِدِينَ

When Allah made (His) covenant with the prophets, (He said): Behold that which I have given you of the Scripture and knowledge. And afterward there will come unto you a messenger, confirming that which ye possess. Ye shall believe in him and ye shall help him. He said: Do ye agree, and will ye take up My burden (which I lay upon you) in this (matter)? They answered: We agree. He said: Then bear ye witness. I will be a witness with you.