Abd al-Rahman bin Samurah (may Allah be pleased with him) said: The Prophet (peace and blessings be upon him) said to me: "O Abd al-Rahman bin Samurah! Never ask for leadership. If it is given to you because you asked, you will be left to it, and if it is given to you without asking, you will be helped. And when you swear an oath about something, and then something else is better than it, give the expiation for your oath and do the better thing."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الأيمان / 19954