Abdul Rahman bin Abi Layla narrates: Whenever we said to Sayyiduna Zayd bin Arqam (may Allah be pleased with him), "Narrate hadith to us," he would say: "We have grown old and have forgotten, and narrating hadith from the Messenger of Allah (peace and blessings be upon him) is a weighty responsibility."
Hadith Referenceالمعجم الكبير للطبراني / باب الزاي / 4959