Musnad Abi Ya'la 4239 — whenever the Messenger of Allah ﷺ set out

It is narrated from Sayyiduna Anas bin Malik (may Allah be pleased with him) that whenever the Messenger of Allah (peace and blessings be upon him) set out on a journey or went out on a military expedition, he would each day seat one of his Companions behind him on his mount. So (on one occasion) Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him) was riding behind the Messenger of Allah (peace and blessings be upon him). He (peace and blessings be upon him) called out to him while he was riding behind him and said: "O Mu'adh bin Jabal!" He said: "Labbayka ya Rasul Allah (Here I am at your service, O Messenger of Allah)." He (peace and blessings be upon him) asked: "Do you know what the right of Allah is over His servants? (That right is) that they testify that there is no god worthy of worship except Allah and that Muhammad (peace and blessings be upon him) is His servant and His Messenger, and that they worship Him alone and do not associate anything with Him." He (peace and blessings be upon him) repeated this saying three times. Then he called out (again) and said: "O Mu'adh!" He said: "Labbayka ya Rasul Allah (Here I am at your service, O Messenger of Allah)." He (peace and blessings be upon him) asked: "Do you know what the right of the servants is over Allah when they have fulfilled this (right)?" He said: "Allah and His Messenger know best." He (peace and blessings be upon him) said: "Indeed, the right of the servants over Allah, when they do this, is that He does not punish them and that He admits them into Paradise."