Sayyiduna Jabir (may Allah be pleased with him) says: Sulayk al-Ghatafani came while the Prophet (peace and blessings be upon him) was delivering the sermon, and the Prophet (peace and blessings be upon him) ordered him to pray two rak'ahs and keep them short, and he said: "When one of you comes while the imam is delivering the sermon, let him pray two rak'ahs and keep them short."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6681