It is narrated from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) knew the opening and comprehensive matters of goodness - or the comprehensive and opening matters of goodness - and we did not know what to say in our prayer until he (peace and blessings be upon him) taught us and said: "Say: al-Tahiyyat (All acts of worship)" Then (the narrator) mentioned a similar hadith.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 9874