Asim al-Ahwal عاصم الأحول · The Book on Traveling

"The Messenger of Allah traveled on a journey and he prayed two Rak'ah for nineteen days." Ibn Abbas said: "So when we would stay somewhere for nineteen (days) we would pray two Rak'ah , and if we stayed longer than that we would complete the Salat."

"I was prayed and the Prophet, Abu Bakr, and Umar were there, so when I sat, I started off with praising Allah, then sending Salat upon the Prophet, then supplicating for myself. So the Prophet said: 'Ask, your request will be granted, ask, your request will be ranted.'"