Syedna Ibn Abbas (may Allah be pleased with them both) narrated: The Messenger of Allah (peace and blessings be upon him) prescribed four rak'ahs for the prayer at home, two rak'ahs for the prayer during travel, and one rak'ah for the prayer during fear.

Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrated: Allah has, through the tongue of your Prophet (peace and blessings be upon him), made obligatory the prayer of residence as four rak‘ahs, the prayer of travel as two rak‘ahs, and the prayer of fear as one rak‘ah.