I and Ibn ʿUmar were considered too young to take part in the battle of Badr.  

اسْتُصْغِرْتُ أَنَا وَابْنُ عُمَرَ  

I and Ibn ʿUmar were considered too young (to take part) in the battle of Badr, and the number of the Emigrant warriors were over sixty (men) and the Ansar were over 249.  

اسْتُصْغِرْتُ أَنَا وَابْنُ عُمَرَ يَوْمَ بَدْرٍ وَكَانَ الْمُهَاجِرُونَ يَوْمَ بَدْرٍ نَيِّفًا عَلَى سِتِّينَ وَالأَنْصَارُ نَيِّفًا وَأَرْبَعِينَ وَمِائَتَيْنِ  

The companions of (the Prophet) Muhammad who took part in Badr, told me that their number was that of Saul's (i.e. Talut's) companions who crossed the river (of Jordan) with him and they were over three-hundred-and-ten men. By Allah, none crossed the river with him but a believer. (See Qur'an 2:249)  

حَدَّثَنِي أَصْحَابُ مُحَمَّدٍ ﷺ مِمَّنْ شَهِدَ بَدْرًا أَنَّهُمْ كَانُوا عِدَّةَ أَصْحَابِ طَالُوتَ الَّذِينَ جَازُوا مَعَهُ النَّهَرَ بِضْعَةَ عَشَرَ وَثَلاَثَمِائَةٍ قَالَ الْبَرَاءُ لاَ وَاللَّهِ مَا جَاوَزَ مَعَهُ النَّهَرَ إِلاَّ مُؤْمِنٌ  

We, the Companions of Muhammad used to say that the number of the warriors of Badr was the same as the number of Saul's companions who crossed the river (of Jordan) with him, and none crossed the river with him but a believer, and the were over three-hundred-and-ten men.  

أَنَّ عِدَّةَ أَصْحَابِ بَدْرٍ عَلَى عِدَّةِ أَصْحَابِ طَالُوتَ الَّذِينَ جَاوَزُوا مَعَهُ النَّهَرَ وَلَمْ يُجَاوِزْ مَعَهُ إِلاَّ مُؤْمِنٌ بِضْعَةَ عَشَرَ وَثَلاَثَمِائَةٍ  

We used to say that the warriors of Badr were over three-hundred-and-ten, as many as the Companions of Saul who crossed the river with him; and none crossed the river with him but a believer.  

أَنَّ أَصْحَابَ بَدْرٍ ثَلاَثُمِائَةٍ وَبِضْعَةَ عَشَرَ بِعِدَّةِ أَصْحَابِ طَالُوتَ الَّذِينَ جَاوَزُوا مَعَهُ النَّهَرَ وَمَا جَاوَزَ مَعَهُ إِلاَّ مُؤْمِنٌ