Muwatta Malik:Zakat:Hadith 593
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، كَانَ يَقُولُ ‏:‏ لاَ تَجِبُ فِي مَالٍ زَكَاةٌ حَتَّى يَحُولَ عَلَيْهِ الْحَوْلُ ‏.‏

Yahya related to me from Malik from Nafi that Abdullah ibn Umar used to say, “Zakat does not have to be paid on property until a year has elapsed over it.”