“The plan of salvation could not be brought about without an atonement… The atoning sacrifice had to be carried out by the sinless Son of God, for fallen man could not atone for his own sins. The Atonement had to be infinite and eternal to cover all men throughout all eternity. Through His suffering and death, the Savior atoned for the sins of all men. His Atonement began in Gethsemane and continued on the cross and culminated with the Resurrection.”

Source: "The Miracle of the Atonement", April 2011 General Conference