That allows shortening Salah (Prayer).

Q: Is it permissible for a traveler to shorten their Salah (Prayer) if they stay in one place for three or six days, or for a whole year? Is it permissible to perform Tayammum (dry ablution) by striking a stone?

A: First: It is not permissible for a traveler who intends to stay in a country for more than four days to shorten their Salah. However, it is permissible for them to shorten their Salah if they stay for less than four days. Second: Taymmum has to be made by means of clean earth. This is based on the Qur'anic Ayah (verse) in which Allah (Exalted be He) says, ...perform Tayammum with clean earth and rub therewith your faces and hands (Tayammum). It is not permissible to make Tayammum by striking on stone and the like. (Part No. 8; Page No. 96) May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.