When three people set out on a journey, they should appoint one of them as their leader
Good hadithعن أبي سعيد وأبي هريرة رضي الله عنهما مرفوعاً: «إذا خرج ثلاثة في سفر فَلْيُؤَمِّرُوا أحدهم».
Abu Sa‘īd and Abu Hurayrah (may Allah be pleased with both of them) reported that the Prophet (may Allah's peace and blessings be upon him) said: "When three people set out on a journey, they should appoint one of them as their leader."
Explanation
The Messenger of Allah (may Allah’s peace and blessings be upon him) commanded travelers to appoint one of them as their leader. It should be the best and most level-headed of them they appoint to manage their affairs, because if they do not appoint one of them as their leader, their affairs would become chaotic.
Source · Narrated by Abu Daoud
From the Hadith Encyclopedia (hadeethenc.com).