Sahih al-Bukhari, Volume 5, Book 59, Hadith 309 (USC-MSA) ⓘ
Narrated Abu 'Is-haq: A man asked Al-Bara' and I was listening, "Did `Ali take part in (the battle of) Badr?" Al-Bara' said, "(Yes). he even met (his enemies) in a duel and was clad in two armors (one over the other).
حَدَّثَنِي أَحْمَدُ بْنُ سَعِيدٍ أَبُو عَبْدِ اللَّهِ، حَدَّثَنَا إِسْحَاقُ بْنُ مَنْصُورٍ، حَدَّثَنَا إِبْرَاهِيمُ بْنُ يُوسُفَ، عَنْ أَبِيهِ، عَنْ أَبِي إِسْحَاقَ، سَأَلَ رَجُلٌ الْبَرَاءَ وَأَنَا أَسْمَعُ، قَالَ أَشَهِدَ عَلِيٌّ بَدْرًا قَالَ بَارَزَ وَظَاهَرَ.
also referenced under: Book 64, Hadith 23 (In-Book) & Hadith 3970 (DarusSalam)