Hadith 511060
Chapter 28: Marriage - كتاب النكاح
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، أَنَّ زَيْدَ بْنَ ثَابِتٍ، كَانَ يَقُولُ إِذَا دَخَلَ الرَّجُلُ بِامْرَأَتِهِ فَأُرْخِيَتْ عَلَيْهِمَا السُّتُورُ فَقَدْ وَجَبَ الصَّدَاقُ .
Yahya related to me from Malik from Ibn Shihab that Zayd ibn Thabit said, "When a man takes his wife to his house and co-habits with her then the bride-price is obliged."
Reference Muwatta Malik 511060
USC-MSA web (English) reference : Book 28, Hadith 13