Arabic hadith text
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، كَانَ يَقُولُ إِذَا جَاوَزَ الْخِتَانُ الْخِتَانَ فَقَدْ وَجَبَ الْغُسْلُ ‏.‏
Translation

Yahya related to me from Malik from Nafi that Abdullah ibn Umarused to say, "When the circumcised part passes the circumcised part,ghusl is obligatory."