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. (IT)
English reference (IT): Book 4, Hadith 630 (IT)
Arabic reference (IT): Book 4, Hadith 606 (IT)