Jesus said
This is My blood of the Covenant which is shed for many for the forgiveness of sins. Matthew 26:28
Peter testified
Neither is there salvation in any other, for there is none other authority under heaven given among men whereby we must be saved. Acts 4:12
When we gentiles were without Christ, we had no hope and were without God in the world, being aliens from the commonwealth of Israel and strangers from the Covenants of promise. Ephesians 2:12
Jesus ordained Paul to be a minister to us and a witness to open our eyes, to turn us from darkness to light and from the power of Satan unto God so we may receive forgiveness of sins and inheritance among those who are sanctified by faith that is in Him. Acts 26:18
Faith in Jesus, whom God sat forth to be an atonement through faith in His blood, declaring His righteousness for the remission of sins that have previously transpired. Romans 3:25
Therefore we conclude that a man is justified by faith without the deeds of the law. Romans 3:28
They which are of faith are the children of Abraham. Galatians 3:7
This includes both the physical descendants of Abraham that are of faith, as well as those of faith among the Gentiles which do not have the law, but by nature do the things contained in the law, show the work of the law written in our hearts. Romans 2:14-15
So we who obey the law and are of faith, both Jew and gentile can say: “Now we, as Isaac was, we are the children of promise.” Galatians 4:28
Romans 9:6-8 tells us that the ‘children of promise’ is Israel. Therefore, we who obey the law and are of faith are, through His grace, God’s Spiritual Israel.
Do we then make void the law through faith? God forbid. We establish the law.
Romans 3:31
Jesus declared: Think not that I am come to destroy the law or the prophets. I am not come to destroy, but to accomplish. Matthew 5:17. For verily I say unto you, till heaven and earth pass away, one jot or one tittle shall in no wise pass from the law until all things are accomplished. Matthew 5:18
Paul states
Know you not brethren (for I speak to them that know the law) how the law has dominion over a man as long as he lives? Romans 7:1
Whosoever commits sin transgresses the law; for sin is transgression of the law.
1 John 3:4
However
The law of the Spirit of life in Christ Jesus has made me free from the law of sin and death. Romans 8:2
For
Christ has redeemed us from the curse of the law, being made a curse for us. Gal 3:13
And for this reason Jesus is the mediator of the New Covenant, that by means of His death for the redemption of the transgressions that were under the First Covenant, they which are called might receive the promise of eternal life. Hebrews 9:15
What if we sin after salvation?
Who is he that condemns? It is Christ that died, yes rather, that is risen again, who is at the right hand of God, making intercession for us. Romans 8:34
Therefore
Seeing that we have a great High Priest that is passed into the heavens, Jesus the Son of God, let us hold fast our profession. Hebrews 4:14
For many did not receive the love of the Truth that they might be saved, and for this reason God sent them strong delusion that they should believe a lie. That they all might be damned who do not believed the truth, but have pleasure in unrighteousness. 2 Thessalonians 2:10-12
So, let us not be
Of them who draw back unto perdition, but of them that have faith and obtain eternal life. Hebrews 10:39
We must guard against strong delusion
By the word of Truth, by the power of God, by the armour of righteousness on the right hand and on the left. 2 Corinthians 6:7
Wherefore take unto you the whole armour of God, that ye may be able to withstand in the evil day, and having done all, to stand. Ephesians 6:13