عَن سَمُرَة بن جُنْدُب قَالَ: أَمَرَنَا رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ إِذَا كُنَّا ثَلَاثَةً أَنْ يَتَقَدَّمَنَا أَحَدُنَا. رَوَاهُ التِّرْمِذِيّ

Samura b. Jundub said

God’s Messenger commanded that when there were three of us one should stand in front. Tirmidhi transmitted it.