Sayyiduna Abu Hurayrah (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "When you travel, let the one who knows the Qur'an best lead you in prayer, even if he is the youngest of you in age; and when he leads you in prayer, he will also be your leader (amir)."
Al-Bazzar recorded it; its chain contains a narrator whom I do not know.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الجهاد / 9306