Tuwa is called "the sacred valley" (al-wadi al-muqaddas) in the Quran. Ta-Ha 20:12 and an-Nazi'at 79:16 relate that Allah called to Moses here and told him to remove his sandals. Al-Qasas 28:30 adds that the call came "from the right side of the valley, in the blessed spot, from the tree".
Commentators have explained "Tuwa" in different ways: as the valley's proper name, or as a description such as "twice sanctified". The valley is generally placed at the foot of Mount Sinai and is traditionally associated with the valley of St Catherine's Monastery, but its exact location is unknown.