Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) narrated: The Messenger of Allah (peace and blessings be upon him) sent out a detachment, and they were martyred. They left behind this message: When you meet your people, convey to them from us that we have met our Lord; we are pleased with Him and He is pleased with us.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 10255