Prayer (Kitab Al-Salat): Details of Commencing Prayer
Dawud :: Book 3 : Hadith 1049
Narrated Qudamah ibn Wabirah:
The Prophet (peace_be_upon_him) said: If anyone omits the Friday prayer without excuse, he must give one dirham or half a dirham, or one sa' or half a sa' of wheat, in alms.