The Bible consistently says that divorce always involves sin on the part of one or both parties. God never intended for anyone to divorce, but mercifully made provision for divorce when immorality occurs. He also mercifully made provision for divorced people to remarry.
If it wasn’t for Jesus’ words about remarriage, no one reading the Bible would have ever thought that remarriage was a sin (except for two very rare cases under the old covenant and for one rare case under the new, namely, remarriage after one was divorced from a Christian as a Christian). We have, however, found a logical way to harmonize what Jesus said about remarriage with what the rest of the Bible teaches. Jesus was not replacing God’s law of remarriage with a stricter law that forbids all remarriage in every case, an impossible law for people who are already divorced and remarried to obey (like trying to unscramble eggs), and one that would create unlimited confusion and lead people to break other laws of God. Rather, He was helping people to see their hypocrisy. He was helping those who believed they would never commit adultery to see that they were committing adultery in other ways, by their lust and by their liberal attitude toward divorce.
As the entire Bible teaches, forgiveness is offered to repentant sinners regardless of their sin, and second and third chances are given to sinners, including divorced people. There is no sin in any remarriage under the new covenant, with the exception of the believer who has been divorced from another believer, which should never occur since true believers are not committing immoralities and there is thus no valid reason to divorce. In such a rare event that they do, both should remain single or be reconciled to each other.