3 Nephi 11
In some ways I can imagine relief in the Saviors voice as he announces that He has drunk out of the bitter cup that the Father had given Him. In the Doctrine and Covenants He indicates that He had some concern that He might shrink from so great a task even after He commenced it. Having completed it He knew that there was nothing left to do which would so challenge Him. Honestly I would expect that He would not give any tone of that relief as He spoke, but He may well have felt it.