Sayyiduna Qabath bin Ashyam (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) said: "Two men praying, one of them leading the other, is more excellent with Allah than four men praying individually; and the prayer of four men, when one of them leads the rest, is more pleasing to Allah than eight men praying individually; and eight men praying, when one of them leads, is more excellent with Allah than a hundred men praying individually."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4965