Prayer (Kitab Al-Salat): Detailed Rules of Law about the Prayer during Journey

Dawud :: Book 4 : Hadith 1226

Narrated Abdullah ibn Abbas:

The Apostle of Allah (peace_be_upon_him) had a stop of seventeen days in Mecca and he shortened the prayer (i.e. prayed two rak'ahs at each time of prayer). Ibn Abbas said: He who stays seventeen days should shorten the prayer; and who stays more than that should offer complete prayer.