The letter of Jude was Jesus’ Earthly brother and his writing in the Bible in Jude does not in any way dispute OSAS when read in proper context.
Jude is warning these believers against the FALSE TEACHERS creeping into the early church. These false teachers were saying that because Jesus paid the penalty for our sins that we can go ahead and sin all we want now without consequences. And the mention of Genesis 6 (where Angels had sexual relations with daughters of men), as well as Genesis 19 (about Sodom) shows that an immoral sexual behavior was involved in the teaching of these false teachers. They are straight out rebelling against God’s authority and teaching others to do the same. Believer’s have freedom in Christ from the penalty of our sins but we also have the indwelling Spirit if God working on our sanctification and this is definitely not the attitude of a real believer.
The context of Jude is the sin and complete condemnation of UNBELIEVING Godless people. An unbeliever has one nature called The Flesh (our sin nature). A true believer of Christ has two natures; the sinful Flesh nature and the Newly Created Spirit of God. A war begins within a believer because the Flesh wants to sin but the Spirit of God now indwelling the believer is the seed of God and never sins (1 John 3:9). When a believer sins, a conviction about it comes from the Holy Spirit within that gnaws at us and helps us to change our mind (Repent) about the act and acknowledge it as a sin which we CONFESS and agree with God. We do not lose our Salvation in this. It is a part of our sanctification until we receive our new resurrected bodies without the Flesh nature in the future. Just as Paul had, it is a real struggle (Romans 7).
Jude was not writing about people who had lost their salvation from the church age! It is a completely different context in Jude. Jude writes about the unbelievers in Exodus. It is not even talking about Salvation by the grace of God to the church although Salvation is foreshadowed. Also, looking at verse 6, we see again the context does not fit the church age believers. He is talking all about fallen angels from Genesis 6 and not about humans who lost salvation. What is the letter of Jude all about? Unbelief and rebellion.
We see here that Jude is encouraging believers in the church age to keep the faith in the free gift of Salvation by faith in Christ alone. And to FIGHT the FALSE TEACHERS. The very idea or teaching that now Christ died for us, that we should go on sinning BECAUSE OF IT, shows the unbelief of these false teachers about what Christ did for us on that cross in the first place.
Yes! Believers on the atonement by Christ for our sins are saved but that does not mean they will not sin nor that they will not struggle with sin. But instead of feeling this fight of the Two Natures inside a believer, these FALSE TEACHERS are not even believers. They intellectually understand Salvation but totally miss the mark and do not have the struggle of Romans 7 within them.
“But ye, beloved, building up yourselves on your most holy faith, praying in the Holy Ghost, Keep yourselves in the love of God, looking for the MERCY of our Lord Jesus Christ UNTO ETERNAL LIFE.” (Jude 20-21 KJV)
Salvation is a gift to be received (Ephesians 2:8-9) and not something that we earn. Only the atonement for sins through Christ crucified saves us. It is not our self righteous efforts. Salvation is by BELIEF on Christ alone. Jesus Himself said,
“He that BELIEVIETH ON HIM is not condemned: but he that BELIEVETH NOT is condemned ALREADY, because he hath not BELIEVED in the name of the only begotten Son of God.” (John 3:18 KJV)
This belief must be REAL though and not just intellectual belief. Judas Iscariot had intellectual belief and even lived with Jesus during His Earthly ministry. Yet, Judas did not really believe.
Christ paid for the sins of the whole world right? Yet, does that mean that unbelievers are saved? No. Does that mean we can just go sin all we want now and that it is just okay to do such without consequences? Paul tells us in Romans 10,
“What then? shall we sin, because we are not under the law, but under grace? God forbid. Know ye not, that to whom ye yield yourselves servants to obey, his servants ye are to whom ye obey; whether of sin unto death, or of obedience unto righteousness? But God be thanked, that ye WERE the servants of sin, but ye have obeyed from the heart that form of doctrine which was delivered you. Being then MADE FREE from sin, ye became the servants of righteousness.” (Romans 10:15-18 KJV)
Before belief on Christ we were Servants of the Flesh alone…servants of sin. After we believed on Christ alone God MADE US FREE FROM SIN and Servants to RIGHTEOUSNESS. This obeying is not of the Law unto Salvation but it is obeying in belief on Christ to save us. The obedience here is belief on Christ and not Law keeping to save us. Now freed from sin through Christ’s atonement on the cross, we HAVE BECOME servants of righteousness. We were given the very righteousness of God in Christ and our lives will change from the new inner man (over time the Holy Spirit guides us and by the renewing of the mind by the Word of God this belief works it’s way outwardly it our life as good works).
Apostle Paul is teaching us all that since we are saved by God’s Grace, that we should be living by the spirit that Christ provided in us. This Spirit of God is the NEW US. Jude is telling these particular believers, where false teachers were creeping in, that they should KEEP the faith and press toward being Holy because the new indwelling Spirit in every believer is Holy. We receive the newly created Spirit of God within us from the very moment of our belief on Christ alone to save us (Paul taught us that in Ephesians 1:13-14), by the only atonement for sin that the Christ provided on the cross; our being born again in the Spirit. Paul tells us to “…Walk in the Spirit, and ye shall not fulfil the lust of the flesh.” (Galatians 5:16 KJV)
These false teachers were not saved because of their unbelief. They are not believers who lost Salvation. There is no mention of loss of Salvation found in Jude that I can see.