I asked Ibn 'Abbas: How should I say prayer when I am in Mecca, and when I do not pray along with the Imam? He said: Two rak'ahs (of prayer) is the Sunnah of Abu'l-Qasim (ﷺ).
Sahih Muslim Book 6, Hadith 8
← Previous Hadith Allah has prescribed the prayer by the tongue of your Apostle (ﷺ) as two rak'ahs for the traveller, four for the resident, and one in danger.

Sahih Muslim Book 6, Hadith 7 Next Hadith → A hadith like this has been narrated by Abu Qatada with the same chain of transmitters.

Sahih Muslim Book 6, Hadith 9