There are over 40,000 different Christian denominations, groups, and sects around the world. All of them have their own Seminaries where they indoctrinate (brainwash, condition, program) their students with their particular brand of theology. All of them have their own "Scholars" (so-called "Experts") in the Scriptures. All their adherents think that their particular brand of theology is the "right" one. They cannot all be right, but they can certainly all be wrong. There are 40,000 different Christian denominations, groups, and sects who teach "You must..." or "You need more...," but only one that says, "It is finished!"
If your beliefs, doctrines, practices, theology, and traditions contradict the very basics of Christianity 101 and the foundation of the New Covenant, the Gospel, and grace, then your system, no matter how committed you are to it, is flawed and bankrupt.
When Jesus uttered, "Tetelestai," He was saying, "It is finished!" What is finished? What does this word mean? During the first century, 'Tetelestai' was used in several different contexts.
- Business Context: Tetelestai stamped on a receipt meant "paid in full" — debt completely settled.
- Judicial Context: Tetelestai marked on a prisoner's record meant "sentence fully served" — penalty fulfilled.
- Military Context: Tetelestai declared by a commander meant "mission accomplished" — victory won.
On the cross, Jesus was declaring, "Your debt of sin is fully paid, the judgment for your sin has been fully served, and the spiritual war against sin, death, and the Devil has been completely won!" This is the first truth that needs to be the foundation of your faith.
Yahweh promised to make a new Covenant, but unlike the previous Covenant, this one would be made with the entire world — Jews and gentiles alike. Yahweh said of this Covenant, it will be "not like the Covenant that I made with their fathers" (Heb. 8:9a). Yahweh promised to put His laws into the minds of the faithful and write them on their hearts (Heb. 8:10b; 10:16b). This does not refer to the Ten Commandments, or the two greatest commandments (which sum up the Ten), because Paul said these were a "ministry of condemnation" and a "ministry of death" (2 Cor. 3) that merely cause us to sin (Rom. 7). It certainly is not the 613 commands of the Law, because the "former commandment is set aside because of its weakness and uselessness (for the Law made nothing perfect)" (Heb. 7:18-19a) and "if that first Covenant had been faultless, there would have been no occasion to look for a second" (Heb. 8:7).
Yahweh promised, "I will be merciful toward their iniquities, and I will remember their sins no more" (Heb. 8:12; 10:17). The author of Hebrews adds, "Where there is forgiveness of these, there is no longer any offering for sin" (10:18). At the Last Supper, Jesus said His blood was being "poured out for many for the forgiveness of sins" (Matt. 26:28). The New Covenant was activated with Jesus' death on the cross (see Heb. 9:16-17). With Jesus' blood, all our sins — past, present, and future — have been completely forgiven (Eph. 1:7), we have been released/freed from our sins (Rev. 1:5b), our sins have been removed from us as far as the East is from the West (Ps. 103:12), and God promised to remember our sins no more (Heb. 8:12; 10:17). If your theology teaches contrary to this, it is another gospel which is no gospel at all, and Paul said such people should be cursed. That is a great indictment! This is the second truth that needs to be the foundation of your faith.
With the New Covenant, Yahweh promised to fulfill everything by His own hand, swearing by Himself. He accomplished this through Christ Jesus. He fulfilled the Law because we could not. He took the punishment that was due us. If your theology and interpretation of certain Bible passages teaches that Yahweh will discipline, chastise, or punish the believer for any sins that he/she commits, then your theology is bankrupt and you have not understood the basics and foundation of Christianity and the Gospel. The full anger, wrath, and punishment of Yahweh was poured out on Christ Jesus at the cross. If Yahweh has to exact more from the believer because of his/her sin, then the sacrifice of Jesus was not sufficient enough to deal with our sin problem. That is heresy!
(From Yahweh's perspective, "there is no longer any condemnation" for sin because Jesus took care of it once and for all on the cross. In this world, however, there are still consequences for sin. Lying, stealing, murdering, etc., all still have worldly consequences, but Yahweh will not judge you for them because He does not hold them against you. If your theology teaches otherwise, it is bankrupt theology that contradicts the New Covenant, the Gospel, and grace. Repent!)
Jesus' work is finished! There will be no encore, no second act. You cannot finish your own work (your righteous deeds are like a menstrual rag), and you cannot add anything to His finished work. All you can do, and all you should do, is rest in His finished work, thanking Him for all He has accomplished for you on your behalf in your place. This is the third truth that needs to be the foundation of your faith.
Read the book of Hebrews some time. Slowly and carefully. It is the most Christ-centric of all the epistles. The entire letter demonstrates how Jesus is better than everything. He is the foundation of our salvation. He is greater than Moses. He is our Great High Priest. He is greater than Melchizedek. He is the Mediator of a Better Covenant. He is the better sacrifice. If you are flirting with Moses, then you are cheating on Jesus! You cannot attempt to date the Law. We broke up! (Rom. 7:4, 6)
Anything that you are taught in any Christian denomination, group, or sect, or in cults who profess to be Christian (Jehovah's Witnesses, Mormons, etc.), that contradicts or rejects these basic foundational beliefs of Christianity is another gospel that makes void the grace of Yahweh. It is bankrupt man-made theology that ignores the New Covenant and the Gospel. These foundational truths are the Gospel! The Good News! If you reject these, it is because you have a heart like the Pharisees and are self-righteous (seeking to earn something from Yahweh by your deeds), and you need to hear Jesus' hard statements in order to break you and bring you to despair so that you look to Him for something better: grace!