Sayyiduna Jabir (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Whoever among you fears that he will not be able to wake up in the last part of the night, he should perform Witr in the early part of the night. And whoever among you hopes that he will perform voluntary prayers in the last part of the night, he should perform Witr in the last part of the night, because the recitation done at the end of the night is attended (by the angels) and it has more virtue."