I believe the Bible says as far as the east is from the west, the Lord will forgive our sins. So, is Matthew 18:8-9 for believers and non-believers?
The verse you are thinking of is Psalm 103:12 which says, “As far as the east is from the west, so far has He removed our transgressions from us.” One has said on this verse, “Just as ‘east is east, and west is west, and never the two shall meet,’ so the believer and his sins will never meet. Those sins have been put out of God’s sight forever by a miracle of love” (William MacDonald). This is a “Psalm of David” and thus he was expressing the forgiveness God offered the Jews in his day. Of course, it was only for BELIEVERS who would believe in and accept God’s gift of forgiveness. David acknowledged his belief in God’s forgiveness in Psalm 32:1-2a, “Blessed is he whose transgression is forgiven, whose sin is covered. Blessed is the man to whom the LORD does not impute iniquity.” The nation remained in unbelief which is true of Israel today. But the day is coming when they will see that their rejection of Christ as their Messiah and having Him crucified by the Romans was allowed by God so He could offer them this forgiveness through the atoning work of Christ on the cross. Isaiah 53:4-6 will then be very precious to them: “Surely He has borne our griefs and carried our sorrows; yet we esteemed Him stricken, smitten of God, and afflicted. But He was WOUNDED FOR OUR TRANSGRESSIONS, He was BRUISED FOR OUR INIQUITIES; the chastisement for our peace was upon Him, and by His stripes we are healed. All we like sheep have gone astray; we have turned, every one, to his own, way; and the LORD has laid on Him the iniquity of us all.” When Israel had Him crucified, they thought He was being punished for HIS SINS, but they will come to see that it was THEIR SINS that put Him on the cross and for which He suffered. Then, and only then, will they realize that their sins have been removed “as far as the east is from the west.” Of course, believers today can apply those verses to us as well, along with other verses that bring out the same truth of our SINS BEING GONE, such as Hebrews 10:17, “And their sins and iniquities will I remember no more.”
Now let’s read Matthew 18:7-9: “Woe to the world because of offenses! For offenses must come, but woe to that man by whom the offense comes! If your hand or foot causes you to sin, cut it off and CAST IT FROM YOU. It is better for you to enter into life lame or maimed, rather than having two hands or two feet, to be CAST INTO THE EVERLASTING FIRE. And if your eye causes you to sin, pluck it out and CAST IT FROM YOU. It is better for you to enter into life with one eye, rather than having two eyes, to be CAST INTO HELL FIRE.” In this passage the Lord Jesus was warning UNBELIEVERS of their sins that will eventually cause them to be “cast into hell.” But He was also giving them a way to escape hell by telling them to “judge the sins they are committing.” Jesus was NOT teaching sinners to literally “cut off their hand or foot and pluck out their eyes”; He was teaching them to judge those acts of sins that were being committed by members of their body. He was teaching them the necessity of JUDGING THEIR SINFUL CONDITION for only then will they be able to see their need of Christ and the salvation He offers them through HIM BEING JUDGED FOR THEIR SINS on the cross (as we just saw in relation to Isaiah 53:4-6). Some have taught that Jesus was teaching sinners that they can be saved and go to heaven “if they cast their sins away from them” but they fail to see what we just saw from Psalm 103:12; it is “God who casts/removes our sins from us” when we accept His gift of forgiveness through His Son and His finished work on the cross. “To Him all the prophets witness that, through His name, whoever believes in Him will receive remission of sins…Therefore let it be known to you, brethren, that through this Man is preached to you the forgiveness of sins; and by Him everyone who believes is justified from all things from which you could not be justified by the law of Moses” (Acts 10:43 and 13:38-39). (DO) (666.5)