But of no avail is the repentance of those who commit evil (for a lifetime) until, when one of them is visited by death, he says, "Indeed now I repent." Nor (likewise does the repentance avail) of those who (spend their lives in unbelief and offer to repent just at the time of death, but) die as unbelievers (since such repentance is not acceptable). For such We have prepared a painful punishment.