It is narrated from Sayyiduna Abd al-Rahman bin Samurah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "O Abd al-Rahman! Never ask for leadership. If you ask for it and it is given to you, you will be left to it (on your own); and if it comes to you without asking, you will be helped. And when you swear an oath about something and something else is better than it, then do the better thing and give the expiation for your oath."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الأيمان / 19841