The crowd that teaches that salvation can be lost, makes excuses for certain sins. They call most sin, "mistakes," and not really "sin." The reason they do that, is because they teach the false doctrine that if a person sins, then he loses his salvation. They know that they do wrong things every day, but in their thinking, they would then have to get "re-saved" every day. Rather than teach that, they teach that only the "really bad" things are "sin," like murder, adultery, etc. But that contradicts the clear teaching of Scripture in James 2:9,10 says, "But IF YE HAVE RESPECT TO PERSONS, YE COMMIT SIN, and are convinced of the law as transgressors. FOR WHOSOEVER SHALL KEEP THE WHOLE LAW, AND YET OFFEND IN ONE POINT, HE IS GUILTY OF ALL." The Bible shows there that just showing partiality or favoritism to certain people over others is sin.
When a person gets saved, ALL OF HIS OR HER SIN is forgiven by the blood of Jesus Christ. I John 1:7 says, "The blood of Jesus Christ his Son cleanseth us from ALL sin." His blood does not just save until that person sins again, but it saves that person ETERNALLY. Hebrews 7:25 says, "Wherefore he is able also TO SAVE THEM TO THE UTTERMOST that come unto God by him, seeing he ever liveth to make intercession for them."
So when a Christian sins, God will speak to that one through His Word, the Bible. If the Christian responds and repents, then no further action is needed. The Lords Supper is a good example of how the Lord works in the lives of Christians. I Corinthians 11:26-32 says, "For as often as ye eat this bread, and drink this cup, ye do show the Lord's death till he come. Wherefore whosoever SHALL EAT this bread, AND DRINK this cup of the Lord, UNWORTHILY, SHALL BE GUILTY of the body and blood of the Lord. But LET A MAN EXAMINE HIMSELF, and so let him eat of that bread, and drink of that cup. For he that eateth and drinketh unworthily, eateth and drinketh damnation to himself, not discerning the Lord's body. FOR THIS CAUSE MANY ARE WEAK AND SICKLY AMONG YOU, AND MANY SLEEP. FOR IF WE WOULD JUDGE OURSELVES, WE SHOULD NOT BE JUDGED. BUT WHEN WE ARE JUDGED, WE ARE CHASTENED OF THE LORD, THAT WE SHOULD NOT BE CONDEMNED WITH THE WORLD."
Before partaking of the Lords Supper, we are told that if we eat "unworthily" (which would be eating it without due reverence for the suffering and sacrifice which it symbolizes; or eating it with known sin in our lives from which we stubbornly will not repent), then that would make us guilty and subject to chastisement from the Lord. On the one hand, we would be eating of the elements that show forth Jesus suffering and death, as though we really cared and appreciated what He has done for us; but on the other hand, by our continuing in sin, it would be like saying, "Who cares that He suffered and died? I am going to continue in sin." That is the attitude that was common at Corinth, and so God judged them. I Corinthians 11:30 says, "For this cause many are weak and sickly among you, and many sleep." Many were sick, and many had even died because they would not repent of their sin.
God will first speak to us from His Word. If we will not repent, then we may suffer physical consequences. If we will not repent at that, then He may take us home to heaven early, because He can no longer trust us here to live like we should. Please notice that this passage on the Lords Supper is VERY CLEAR that the Christian is NEVER placed back in the category with the unsaved, even though he (the Christian) may die because of his sin. "But when we are judged, we are chastened of the Lord, that we should NOT BE CONDEMNED WITH THE WORLD."
I Corinthians 3:11-17 also makes it clear that the Christian can never lose his salvation, but he can certainly lose his heavenly rewards, and suffer physical death because of his lack of repentance of sin. "For other foundation can no man lay than that is laid, which is Jesus Christ. Now if any man build upon this foundation gold, silver, precious stones, wood, hay, stubble; Every man's work shall be made manifest: for the day shall declare it, because it shall be revealed by fire; and the fire shall try every man's work of what sort it is. If any man's work abide which he hath built thereupon, he shall receive a reward.
If any man's work shall be burned, HE SHALL SUFFER LOSS: BUT HE HIMSELF SHALL BE SAVED; YET SO AS BY FIRE. Know ye not that ye are the temple of God, and that the Spirit of God dwelleth in you? IF ANY MAN DEFILE THE TEMPLE OF GOD, HIM SHALL GOD DESTROY; for the temple of God is holy, which temple ye are."
I John 2:15-17 tells us, "Love not the world, neither the things that are in the world. If any man love the world, the love of the Father is not in him. For all that is in the world, the lust of the flesh, and the lust of the eyes, and the pride of life, is not of the Father, but is of the world. And the world passeth away, and the lust thereof: but he that doeth the will of God abideth for ever." James 1:12-15 says, "Blessed is the man that endureth temptation: for when he is tried, he shall receive the crown of life, which the Lord hath promised to them that love him. Let no man say when he is tempted, I am tempted of God: for God cannot be tempted with evil, neither tempteth he any man: But every man is tempted, when he is drawn away of his own lust, and enticed. Then when lust hath conceived, it bringeth forth sin: and sin, when it is finished, bringeth forth death."
The Lord promises in Hebrews 13:5, "I will never leave thee, nor forsake thee," and that is true. If we sin, He is not going to turn His back on us and disown us. What He is going to do is come after us with chastening. And if that will not work, then He will take us home early. That can be the result of church discipline, as is seen in I Corinthians 5:3-5, "For I verily, as absent in body, but present in spirit, have judged already, as though I were present, concerning him that hath so done this deed, In the name of our Lord Jesus Christ, when ye are gathered together, and my spirit, with the power of our Lord Jesus Christ, To deliver such an one unto Satan FOR THE DESTRUCTION OF THE FLESH, THAT THE SPIRIT MAY BE SAVED in the day of the Lord Jesus." The spirit of the Christian is saved, but God may allow his flesh to be destroyed because of his sin and lack of repentance.