If there was no revelation, there would be no responsibility to believe. Humans would not go to hell for rejecting it. Then how is revelation and the sending of prophets (عليهم السلام) a mercy to us?
Divine Mercy Through the Prophet Muhammad ﷺ
Divine mercy through the Prophet ﷺ
Second Station of the Fourteenth Flash
Mysteries of بسم الله الرحمن الرحيم [In the name of Allah the Merciful the Compasstionate]