So now have sexual relations with them and seek that which Allah has ordained for you ( offspring ) , and eat and drink until the white thread ( light ) of dawn appears to you distinct from the black thread ( darkness of night ) , then complete your Saum ( fast ) till the nightfall . And do not have sexual relations with them ( your wives ) while you are in I 'tikaf ( i.e. confining oneself in a mosque for prayers and invocations leaving the worldly activities ) in the mosques .