حَدَّثَنَا مُحَمَّدُ بْنُ وَزِيرٍ الْوَاسِطِيُّ، حَدَّثَنَا إِسْحَاقُ بْنُ يُوسُفَ الأَزْرَقُ، عَنْ سُفْيَانَ، عَنْ عُبَيْدِ اللَّهِ بْنِ عُمَرَ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، قَالَ عُرِضْتُ عَلَى رَسُولِ اللَّهِ صلى الله عليه وسلم فِي جَيْشٍ وَأَنَا ابْنُ أَرْبَعَ عَشْرَةَ فَلَمْ يَقْبَلْنِي فَعُرِضْتُ عَلَيْهِ مِنْ قَابِلٍ فِي جَيْشٍ وَأَنَا ابْنُ خَمْسَ عَشْرَةَ فَقَبِلَنِي ‏.‏ قَالَ نَافِعٌ وَحَدَّثْتُ بِهَذَا الْحَدِيثِ عُمَرَ بْنَ عَبْدِ الْعَزِيزِ فَقَالَ هَذَا حَدُّ مَا بَيْنَ الصَّغِيرِ وَالْكَبِيرِ ‏.‏ ثُمَّ كَتَبَ أَنْ يُفْرَضَ لِمَنْ يَبْلُغُ الْخَمْسَ عَشْرَةَ ‏.‏ حَدَّثَنَا ابْنُ أَبِي عُمَرَ، حَدَّثَنَا سُفْيَانُ بْنُ عُيَيْنَةَ، عَنْ عُبَيْدِ اللَّهِ بْنِ عُمَرَ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، عَنِ النَّبِيِّ صلى الله عليه وسلم نَحْوَ هَذَا وَلَمْ يَذْكُرْ فِيهِ أَنَّ عُمَرَ بْنَ عَبْدِ الْعَزِيزِ كَتَبَ أَنَّ هَذَا حَدُّ مَا بَيْنَ الصَّغِيرِ وَالْكَبِيرِ ‏.‏ وَذَكَرَ ابْنُ عُيَيْنَةَ فِي حَدِيثِهِ ‏.‏ قَالَ نَافِعٌ فَحَدَّثْنَا بِهِ عُمَرَ بْنَ عَبْدِ الْعَزِيزِ فَقَالَ هَذَا حَدُّ مَا بَيْنَ الذُّرِّيَّةِ وَالْمُقَاتِلَةِ ‏.‏ قَالَ أَبُو عِيسَى هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ ‏.‏ وَالْعَمَلُ عَلَى هَذَا عِنْدَ أَهْلِ الْعِلْمِ وَبِهِ يَقُولُ سُفْيَانُ الثَّوْرِيُّ وَابْنُ الْمُبَارَكِ وَالشَّافِعِيُّ وَأَحْمَدُ وَإِسْحَاقُ يَرَوْنَ أَنَّ الْغُلاَمَ إِذَا اسْتَكْمَلَ خَمْسَ عَشْرَةَ سَنَةً فَحُكْمُهُ حُكْمُ الرِّجَالِ وَإِنِ احْتَلَمَ قَبْلَ خَمْسَ عَشْرَةَ فَحُكْمُهُ حُكْمُ الرِّجَالِ ‏.‏ وَقَالَ أَحْمَدُ وَإِسْحَاقُ الْبُلُوغُ ثَلاَثَةُ مَنَازِلَ بُلُوغُ خَمْسَ عَشْرَةَ أَوْ الاِحْتِلاَمُ فَإِنْ لَمْ يُعْرَفْ سِنُّهُ وَلاَ احْتِلاَمُهُ فَالإِنْبَاتُ يَعْنِي الْعَانَةَ ‏.‏

Narrated Nafi': that Ibn 'Umar said: "I was reviewed before the Messenger of Allah (PBUH) in the army, and I was fourteen years old, but he did not accept me. Then I was reviewed before him in the army later while I was fifteen years old, and he accepted me." Nafi' said: "I narrated this Hadith to 'Uman bin 'Abdul Azeez and he said: 'This is the limit that distinguishes between childhood and adulthood.' Then he wrote to give salaries to whoever reached fifteen years old." (Another chain) from Nafi', from Ibn 'Umar from the Prophet (PBUH) and it is similar, but he did not mention in it that 'Umar bin 'Abdul-'Aziz wrote that this is the limit that distinguishes between youth and childhood and adulthood. In his narration, Ibn 'Uyainah said (that Nafi' said): "I narrated it to 'Umar bin 'Abdul-'Aziz and he said: 'This is the limit that distinguishes between children and soldiers.'" Translation Not Available

Book reference: Jamiya Tirmidhi Book 15 Hadith 1361
Web reference: Jamiya Tirmidhi Volume 3 Book 13 Hadith 1361