That is truly blasphemy against The Word of God.
The 'once saved, always saved' (OSAS) doctrine FROM MEN is not written in God's Word.
The New Testament has ALWAYS taught there is a CONDITION TO REMAIN IN CHRIST to be saved! And that is especially in regard to Apostle Paul's Epistles!
We are given many Scripture instances of WARNINGS by Lord Jesus and His Apostles against DECEPTION for the END of this world. Even just prior to the 7th Vial being poured out when Jesus returns to end this present world, He gave His Church a major WARNING...
Rev 16:15-17
15 Behold, I come as a thief. Blessed is he that watcheth, and keepeth his garments, lest he walk naked, and they see his shame.
16 And He gathered them together into a place called in the Hebrew tongue Armageddon.
17 And the seventh angel poured out his vial into the air; and there came a great voice out of the temple of heaven, from the throne, saying, "It is done."
KJV
What Is OSAS?
The OSAS doctrine I speak of that goes AGAINST The Word of God is not simply about the idea of God's Grace. Those false ones on that OSAS doctrine misapply God's Grace in trying to make you think anyone against OSAS must be against God's Grace. That is a false assumption by those blasphemers to try and trick you!
Men's false OSAS doctrine believes, and teaches, that once you have believed on Jesus Christ, and been baptized, then YOU HAVE NEVER AGAIN A NEED TO DO REPENTANCE OF FUTURE SINS! That's the 'meat' of their false doctrine in a nutshell.
And a 2nd part to that is the false idea that NO MATTER WHAT EVIL A BELIEVER DOES, they will still be SAVED!
So DOES... The New Testament teach that those in Christ NEVER have future need to repent to Jesus of future sin? No, of course not. The very subject by Apostle John in 1 John 1 is our need to be aware of future sin, and repent to Jesus asking forgiveness, and He promises to cleanse us of all sin. And he further says those who deny that they have sin make Jesus a liar. Those OSAS liars actually go so far and try to claim Apostle John wasn't even speaking those things in 1 John 1 to Christian believers!
Jesus' prayer He gave to His disciples, AND US, in Luke 11, like, "Our Father Which art in heaven, Hallowed by Thy name...," was not given just to Christ's Apostles, nor just to Catholics. It is given for ALL CHRISTIANS in Christ's Church. And notice Luke 11:4 Lord Jesus included in it asking FORGIVENESS OF SINS, and even forgiveness of those who sin against us!
Who Is Actually Behind OSAS?
Well, ask yourselves, who would want us to be found with iniquity when Jesus does appear? The devil would love that of course. The devil wants us to sin and NOT CARE IF WE SIN, NOR BE WATCHING OURSELVES TO SEE IF WE ARE SINNING. And the devil certainly DOES NOT want us to REPENT TO JESUS if after we have discovered ourselves in a sin!
Now I'm not saying the believer that refuses to repent of future sins will not be saved by Jesus, but Lord Jesus DID give us the Matthew 7 example of those who will claim they did many wonderful works in His name, yet He will tell those to get away from Him because of their working 'iniquity'.
And the fact still remains, like Apostle Paul showed in Romans 7, as long as we are in these imperfect flesh bodies, we are still going to slip up and sin at times. We can never... be literal perfect without sin in these flesh vehicles. Our flesh body is of this present world and is under the "law of sin" according to Apostle Paul. It is our inner spirit that desires to follow God and His laws. Yet the two parts battle against each other, like Paul said. This is why John showed we need to REPENT to Jesus in 1 John 1. And ONLY THEN, we are COUNTED AS PERFECT through His saving Grace and remain in the walk with Him.
Party It Up: The Goal of OSAS:
That is the GOAL of man's OSAS doctrine. "Hey, all my sins are already covered, so I don't have to think about sinning any more! It's all forgiven AUTOMATICALLY, FOR EVER! So LET'S PARTY!!!
That's the attitude that has taken over those OSAS Churches. They aren't guarding against deception, and definitely no longer checking theirselves for sin, so life then becomes just one big party. This is actually the attitude Lord Jesus WARNED AGAINST after He gave the 7 Signs of the end in His Olivet discourse, and spoke of His return...
Matt 24:48-51
48 But and if that evil servant shall say in his heart, "My lord delayeth his coming";
49 And shall begin to smite his fellowservants, and to eat and drink with the drunken;
50 The lord of that servant shall come in a day when he looketh not for him, and in an hour that he is not aware of,
51 And shall cut him asunder, and appoint him his portion with the hypocrites: there shall be weeping and gnashing of teeth.
KJV
And those also would deny recognizing Jesus' 7 Messages to the 7 Churches in Asia (Minor) are still ACTIVE for ALL Churches today, because He showed in many of those Messages about the day of His return, and how they would be found if they refused to REPENT. (see Revelation 2 & 3).