I asked Allah's Messenger (ﷺ) to teach me an invocation so that I may invoke Allah with it in my prayer. Hetold me to say, "Allahumma inni zalumtu nafsi zulman kathiran, Wala yaghfiru dh-dhunuba illa anta,fa ghfir li maghfiratan min `indika, wa r-hamni, innaka anta l-ghafuru r-rahim (O Allah! I have donegreat injustice to myself and none except You forgives sins, so bestow on me a forgiveness from You,and Have Mercy on me, You are the Forgiver, the Merciful).