Abu Musa Ashari reported,

I came to the Messenger of Allah ﷺ with a group of the Asharis asking him to provide us with mounts. He said, "By Allah, I will not give you mounts, and I have nothing to mount you on."We waited as long as Allah willed, then some camels were brought to him, and he ordered that we be given three fine she-camels. When we set off, some of us said to one another, "Allah will not bless us. We came to the Messenger of Allah ﷺ asking for mounts, and he swore he would not provide us with any."Abu Musa said, So we went back to the Prophet ﷺ and mentioned this to him. He said, "It was not I who provided you with mounts, but Allah who provided them. By Allah, I never swear an oath and then see something better than it without expiating my oath and doing what is better."

أخبرنا قتيبة قال حدثنا حماد عن غيلان بن جرير عن أبي بردة

عن أبي موسى الأشعري قال

أتيت رسول الله ﷺ في رهط من الأشعريين نستحمله فقال والله لا أحملكم وما عندي ما أحملكم ثم لبثنا ما شاء الله فأتي بإبل فأمر لنا بثلاث ذود فلما انطلقنا قال بعضنا لبعض لا يبارك الله لنا أتينا رسول الله ﷺ نستحمله فحلف أن لا يحملنا قال أبو موسى فأتينا النبي ﷺ فذكرنا ذلك له فقال ما أنا حملتكم بل الله حملكم إني والله لا أحلف على يمين فأرى غيرها خيرا منها إلا كفرت عن يميني وأتيت الذي هو خير