The Family of Imran
إِذْ تَقُولُ لِلْمُؤْمِنِينَ أَلَن يَكْفِيَكُمْ أَن يُمِدَّكُمْ رَبُّكُم بِثَلَـٰثَةِ ءَالَـٰفٍ مِّنَ ٱلْمَلَـٰٓئِكَةِ مُنزَلِينَ
[Remember] when you said to the believers, "Is it not sufficient for you that your Lord should reinforce you with three thousand angels sent down?
Nearby ayahs help place verse 3:124 in sequence and meaning.
إِذْ هَمَّت طَّآئِفَتَانِ مِنكُمْ أَن تَفْشَلَا وَٱللَّهُ وَلِيُّهُمَا ۗ وَعَلَى ٱللَّهِ فَلْيَتَوَكَّلِ ٱلْمُؤْمِنُونَ
When two parties among you were about to lose courage, but Allah was their ally; and upon Allah the believers should rely.
وَلَقَدْ نَصَرَكُمُ ٱللَّهُ بِبَدْرٍ وَأَنتُمْ أَذِلَّةٌ ۖ فَٱتَّقُوا۟ ٱللَّهَ لَعَلَّكُمْ تَشْكُرُونَ
And already had Allah given you victory at [the battle of] Badr while you were few in number. Then fear Allah; perhaps you will be grateful.
بَلَىٰٓ ۚ إِن تَصْبِرُوا۟ وَتَتَّقُوا۟ وَيَأْتُوكُم مِّن فَوْرِهِمْ هَـٰذَا يُمْدِدْكُمْ رَبُّكُم بِخَمْسَةِ ءَالَـٰفٍ مِّنَ ٱلْمَلَـٰٓئِكَةِ مُسَوِّمِينَ
Yes, if you remain patient and conscious of Allah and the enemy come upon you [attacking] in rage, your Lord will reinforce you with five thousand angels having marks [of distinction]
وَمَا جَعَلَهُ ٱللَّهُ إِلَّا بُشْرَىٰ لَكُمْ وَلِتَطْمَئِنَّ قُلُوبُكُم بِهِۦ ۗ وَمَا ٱلنَّصْرُ إِلَّا مِنْ عِندِ ٱللَّهِ ٱلْعَزِيزِ ٱلْحَكِيمِ
And Allah made it not except as [a sign of] good tidings for you and to reassure your hearts thereby. And victory is not except from Allah, the Exalted in Might, the Wise -