Two men in a cave with an army outside
Abū Bakr could see the feet of the men searching. This is what he was told.
إِلَّا تَنصُرُوهُ فَقَدْ نَصَرَهُ ٱللَّهُ إِذْ أَخْرَجَهُ ٱلَّذِينَ كَفَرُوا۟ ثَانِىَ ٱثْنَيْنِ إِذْ هُمَا فِى ٱلْغَارِ إِذْ يَقُولُ لِصَـٰحِبِهِۦ لَا تَحْزَنْ إِنَّ ٱللَّهَ مَعَنَا ۖ فَأَنزَلَ ٱللَّهُ سَكِينَتَهُۥ عَلَيْهِ وَأَيَّدَهُۥ بِجُنُودٍ لَّمْ تَرَوْهَا وَجَعَلَ كَلِمَةَ ٱلَّذِينَ كَفَرُوا۟ ٱلسُّفْلَىٰ ۗ وَكَلِمَةُ ٱللَّهِ هِىَ ٱلْعُلْيَا ۗ وَٱللَّهُ عَزِيزٌ حَكِيمٌ
…idh yaqūlu li-ṣāḥibihi lā taḥzan inna-llāha maʿanā.
“If you do not aid him [i.e., the Prophet (ﷺ)] - Allāh has already aided him when those who disbelieved had driven him out [of Makkah] as one of two,1 when they were in the cave and he [i.e., Muḥammad (ﷺ)] said to his companion, "Do not grieve; indeed Allāh is with us." And Allāh sent down His tranquility upon him and supported him with soldiers [i.e., angels] you did not see and made the word2 of those who disbelieved the lowest,3 while the word of Allāh4 - that is the highest. And Allāh is Exalted in Might and Wise.”
Where this comes from
Abū Bakr said that if one of them looked down at his feet he would see them. The reply was not a plan or a reassurance about the odds. It was three words about who else was in the cave.
Source
The Qur'an · 9:40
- Qur'anic text in the Uthmani script via Quran.com; translation: Saheeh International