Abdullah bin Amr narrated a hadith during the Battle of Jamajim, saying: A man asked Sayyiduna Adi bin Hatim (may Allah be pleased with him) for help, so he swore that he would not give him anything. Then he said: I wish I had not heard from the Messenger of Allah (peace and blessings be upon him), he (peace be upon him) was saying: "If a person swears an oath about something, then sees something else as better, he should do what is better and then offer expiation for his oath."
Hadith Referenceسنن دارمي / من النذور و الايمان / 2382
Sayyiduna Abdur Rahman bin Samurah (may Allah be pleased with him) said: The Messenger (peace and blessings of Allah be upon him) said to him: "O Abdur Rahman bin Samurah! Do not seek leadership (authority or governorship), because if you are given leadership as a result of asking for it, you will be left to it (without divine help), but if you are given leadership without asking for it, you will be helped in it (by Allah). And if you swear an oath about something and then see that something else is better than it, then offer expiation for your oath and do that which is better."
Hadith Referenceسنن دارمي / من النذور و الايمان / 2383
Hadith Gradingتحقیق (حسین سلیم أسد الدارانی):إسناده صحيح وأخرجه البخاري في الأحكام، [مكتبه الشامله نمبر: 2391]
Hadith Takhrijاس روایت کی سند صحیح اور حدیث متفق علیہ ہے۔ دیکھئے: [بخاري 7146، 7147] ، [مسلم 1652] ، [أبوداؤد 3277] ، [ترمذي 1529] ، [نسائي 3792] ، [ابن الجارود 929] و [ابن حبان 4248]