Lady Aisha (may Allah be pleased with her) narrates that when the Messenger of Allah (peace and blessings be upon him) performed any prayer, he liked to be consistent and regular in it. And whenever sleep, illness, or any difficulty prevented him (peace and blessings be upon him) from performing the Tahajjud prayer, he (peace and blessings be upon him) would offer twelve rak‘ahs during the day. This is the narration of Yahya bin Sa‘eed.