بُلُوغُ الْمَرَامِ
Bulugh al-Maram 606
The Book of Zakah
وَلِلتِّرْمِذِيِّ; عَنِ اِبْنِ عُمَرَ: { مَنِ اِسْتَفَادَ مَالًا, فَلَا زَكَاةَ عَلَيْهِ حَتَّى يَحُولَ اَلْحَوْلُ } وَالرَّاجِحُ وَقْفُه ُ [1] .
Ibn Umar (RAA) narrated, ‘Whoever earns any money, he is not liable to pay Zakah, until the period of a year has passed (while still possessing the same amount of money).’ Related by At-Tirmidhi.
Sunnah.com reference: Book 4, Hadith 9