أَنَّهُ كَانَ عِنْدَ جَابِرِ بْنِ عَبْدِ اللَّهِ هُوَ وَأَبُوهُ، وَعِنْدَهُ قَوْمٌ فَسَأَلُوهُ عَنِ الْغُسْلِ،. فَقَالَ يَكْفِيكَ صَاعٌ. فَقَالَ رَجُلٌ مَا يَكْفِينِي. فَقَالَ جَابِرٌ كَانَ يَكْفِي مَنْ هُوَ أَوْفَى مِنْكَ شَعَرًا، وَخَيْرٌ مِنْكَ، ثُمَّ أَمَّنَا فِي ثَوْبٍ.
Abu Ja'far reported that he and his father were with Jabir ibn Abdullah, while some people were with him, and that they asked him about the ritual bath (ghusl). He said, “A sa' is enough for you.” A man said, “It is not enough for me.” …
also in Sahih al-Bukhari 256