Ayyub bin A'idh al-Ta'i (may Allah have mercy on him) said: I said to al-Sha'bi (may Allah have mercy on him): "A man vowed that he would slaughter his son." He said: "It seems you are one of those who rely on analogy. I do not know anyone among the people who sought knowledge across the regions more than Masruq (may Allah have mercy on him)." He said: "There is no vow in disobedience."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الأيمان / 20058