Divorce is tragic for two reasons. First, marriage is designed by God to be indivisible. ”The two shall become one flesh.” As John Murray writes,
“Marriage is grounded in this male and female constitution as to its nature it implies that the man and the woman are united in one flesh; as to its sanction, it is divine; as to its continuance it is permanent. The import of all this is that marriage from its very nature and from the divine institution by which it is constituted is ideally indissoluble. It is not a contract of temporary convenience and not a union that may be dissolved at will.” (J. Murray, Divorce [Philadelphia: Presbyterian and Reformed, 1974], p. 29)
Secondly, marriage is God’s work. He made marriage possible and issued a command to the first couple to be fruitful and multiply. From every angle, it was God who established marriage. ” What God has joined together, let not man separate” (Mark 10:9). Again Professor John Murray reminds us:
Divorce is contrary to the divine institution, and contrary to the nature of marriage, contrary to the divine action by which the union is effected. It is precisely here that its wickedness becomes singularly apparent―it is the sundering by man of a union God has constituted. Divorce is the breaking of a seal which has been engraven by the hand of God” (Murray, Divorce, p. 33).
I preached on “What Jesus Said about Marriage and Divorce” recently. Read or listen.

