All evidence in the Bible contradicts what the Mormon Church claims about the atonement of Jesus. There isn’t anything in the Bible that remotely suggests the payment for sin took place in the Garden of Gethsemane yet here we have a bold teaching claiming otherwise.
Ask your Mormon friend what they think about John 18:11.
Howard W. Hunter, His Final Hours, Ensign Magazine, May 1974, pg. 1; “Christ’s agony in the garden is unfathomable by the finite mind, both as to intensity and cause. … In that hour of anguish Christ met and overcame all the horrors that Satan … could inflict. …In some manner, actual and terribly real though to man incomprehensible, the Savior took upon Himself the burden of the sins of mankind from Adam to the end of the world.” (James E. Talmage, Jesus the Christ, Deseret Book Co., 1962, p. 613.)”