It is narrated from Sayyiduna Mihjan (may Allah be pleased with him) that he was in the gathering of the Messenger of Allah (peace and blessings be upon him) when the muezzin gave the call to prayer. The Messenger of Allah (peace and blessings be upon him) stood up for prayer, performed the prayer, and then returned to find that Mihjan (may Allah be pleased with him) was still sitting in his place. The Messenger of Allah (peace and blessings be upon him) asked: "What prevented you from praying with us? Are you not a Muslim?" Mihjan (may Allah be pleased with him) replied: "Why not! But I had already performed the prayer at home." The Messenger of Allah (peace and blessings be upon him) said: "When you come to the mosque, perform the congregational prayer, even if you have already prayed alone before."
Hadith Referenceالسنن المأثورة / باب ما جاء في الصلاة في السفر / 6
Hadith Takhrijسنن نسائی، الامامة، باب اعادة الصلاة مع الجماعة بعد صلاة الرجل لنفسه، رقم: 857 وقال الالباني : صحيح، وصححه ابن حبان في صحيحه والحاكم في المستدرك 1/244.