By essence we mean, the most important or effectual ingredient of a thing. (1Cor. 11:23-26)
It can be safely said that the facts that Jesus died for the sins of the world on the cross of Calvary and that He is the anointed One, the Son of the living God, are at the very top of the list of the most effectual ingredients of our Christian faith (cons. Isa. 53:4-11; Matt. 16:21-23; Rom. 5:6-8; 1Cor. 15:1-3; 2Cor. 5:19; Matt. 16:13-18; Mk. 1:1; Lk. 1:35; Jn. 1:49).
It is this fact of Jesus’ death for mankind’s sins that is signified in the ordinance referred to in the sub-text (1Cor. 11:23-26 cp. Matt. 26:26-28). It is also the facts of Jesus dying a vicarious death for all man’s and His being the only begotten Son of God that mark out Christianity from all other religious and semi-religious ideologies.
It is indeed these truths that lead to salvation and nothing more (cons. Acts. 8:35-39; 16:27-34; 1Cor. 15:1-3; 1Pet. 3:18).
It should be strongly noted that, it is the denial of these truths that renders any religious ideology false, no matter how good its tenets may seem to be.