Matthew 5:31-32 Marriage, Divorce, And Remarriage.
The certificate that Jesus refers to referred to matters beyond adultery (v. 31; Dt. 24:1), because the civil law code made provision for capital punishment for adultery (Lev. 20:10). Therefore the certificate was for reasons other than adultery – all of which Jesus says stemmed from hardness of heart. Jesus is here saying that divorce is permitted in the church as part of the ethics of the kingdom, but only for the same grounds as is permitted capital punishment in the civil sphere – namely adultery. However, Jesus is actually saying much more. Jesus is saying that anyone who divorces their spouse for reasons other than adultery actually causes them to commit adultery (v. 32 Cf. Lk. 16:17-18). What seems clear from these verses is, this would only be the case if the innocent divorcee actually remarried, as the latter part of the verse may suggest, and anyone who married her so divorced. However, it seems also clear, that anyone who divorces their spouse without grounds and marries another is guilty of adultery, and in this case the first spouse would continue to be innocent, but now free to remarry.