Over the next several days I am going to devote time here to consider The Gospel of God, as is found in Isaiah 52:13 - 53:12. Therein is taught The Penal Substitutionary Atonement. While considering this passage of scripture I shall visit other portions of scripture that are related to that topic.
In The Penal Substitutionary Atonement model we learn that Jesus the Christ, the Son of the living God - God the Son, the Second Person of the Trinity - took upon Himself, His infinitely holy Self, the sins of those who believe, and then suffered the wrath of God the Father upon those sins. He bore the believer's sins, and in the believer's stead, the wrath of God the Father upon those sins, while being scourged and hung upon the cross. He bled and died, paying for those sins, so that the believer would not have to. God the Father accepted that sacrifice of Christ on the cross, and, as a result, He rose from the dead on the third day. He ascended into Heaven, to the Father's right hand, where He is now making intercession for those who believe in Him.
Over the centuries this model of the Atonement has suffered scorn from wicked men; men who say that this model is "cosmic child abuse", or that such teaching is "barbaric". Among those who talk like that are those of the Papal Cult. However, I personally use this as a litmus test for whomever I decide to fellowship with. If I detect that some professing Christian does not hold to this model of the atonement then I walk away from them, and have nothing to do with them. In fact, I just unfriended a guy here on Facebook because I discovered that he did not hold to that model.
In this age of ecumenism I believe that it is wise to examine the beliefs of those who are calling for a coming together of believers. Me personally, if I detect one not holding to that model, I won't have anything to do with them.