Sahih Muslim Book 4, Hadith Number 1903.

Chapter : Shortness of prayer and surmon.

Jabir b. ‘Abdullah reported: Sulaik Ghatafani came on Friday when the Messenger of Allah (may peace be upon him) was delivering the sermon. He (Sulaik) sat down. He (the Holy Prophet) said to him: O Sulaik I stand and observe two rak’ahs and make them short, and then said: When any one of you comes on Friday, while the Imam delivers the sermon, he should observe two rak’ahs and should make them short.