It is narrated from Sayyiduna Marthad bin Abi Marthad al-Ghanawi (may Allah be pleased with him) - who was one of the Companions who fought at Badr - that the Messenger of Allah (peace and blessings be upon him) said: "If it pleases you that your prayer be accepted, then let the best of you lead you in prayer, for they are your representatives between you and your Lord."
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17908