Musa bin Talhah (may Allah have mercy on him) narrates: "I went to Sayyiduna Mu'awiyah bin Abi Sufyan (may Allah be pleased with them both), and when I was about to leave he called me and said: 'O my nephew, I am entrusting you with a hadith that I heard from the Messenger of Allah (peace and blessings be upon him).' Then he said: 'I bear witness that I heard the Messenger of Allah (peace and blessings be upon him) say: Talhah is among those who have fulfilled their vow (pledge).'" That is: what he had pledged to Allah.
Imam al-Tabarani (may Allah have mercy on him) said: "This hadith is not narrated from Sayyiduna Mu'awiyah (may Allah be pleased with him) except with this chain; Ishaq bin Yahya bin Talhah is alone in narrating it."
Hadith Referenceالمعجم الأوسط / باب القاف / 5000
Hadith Takhrij«أخرجه الترمذي فى «جامعه» برقم: 3202، 3740، وابن ماجه فى «سننه» برقم: 126، 127، والطيالسي فى «مسنده» برقم: 1051، والطحاوي فى «شرح مشكل الآثار» برقم: 3562، والطبراني فى «الكبير» برقم: 739»