Suwayd heard Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) say, when Abu Ubaydah was defeated: If they had come to me, I would have been their army or group. (b) Concerning the hadiths of the pledge of allegiance: obedience is to be given only according to one's ability.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 18085