Musnad Ahmad Hadith 19622

It is narrated from Abu Musa (may Allah be pleased with him) that once I, along with a group of Ash'aris, presented ourselves before the Prophet Muhammad (ﷺ). We requested animals for riding from the Prophet (ﷺ), so the Prophet (ﷺ) said, "By Allah! I cannot provide you with mounts, for I do not have anything to mount you on." We stayed there for a while, as long as Allah willed, then the Prophet (ﷺ) ordered for three camels with bright foreheads to be given to us. When we were about to leave, one of us said to the other, "We came to the Prophet (ﷺ) requesting mounts, and the Prophet (ﷺ) swore an oath that he would not give us mounts. Let us go back and remind the Prophet (ﷺ) of his oath." So we again presented ourselves before the Prophet (ﷺ) and said, "O Messenger of Allah! We came to you requesting mounts, and you swore an oath that you would not give us mounts, yet you have given us animals?" The Prophet (ﷺ) said, "I did not provide you with mounts, rather Allah did. By Allah! If Allah wills, whenever I take an oath and then see something better, I will choose that which is better and offer expiation for my oath."