Sayyiduna Thawban (may Allah be pleased with him) narrates: We were traveling with the Prophet (peace and blessings of Allah be upon him). He said: "This journey is a cause of hardship and burden, so when a person performs Witr, he should also perform two rak'ahs. If he wakes up (at the time of Fajr prayer), then fine, otherwise these two will suffice for him."