Musnad Ahmad 30:3684

'Abdullah ibn Yazid narrated to us, Haywah narrated to us, Abu Sakhr narrated to me, that Yazid ibn 'Abdullah ibn Qusayt informed him, from Abu Hurayrah, from the Messenger of Allah (peace and blessings of Allah be upon him), who said: "There is no one who sends greetings of peace (salam) upon me, except that Allah, the Almighty and Majestic, returns my soul to me so that I may return the greeting of peace to him."