Reading His teachings, we realize that Jesus preached a very high moral standard. We can assume His adversaries know this, so when they ask Him about divorce, and Mark calls it a "test," it is likely because Herod had married a divorced woman. In Mark 6 we read "For John had been saying to Herod, "it is not lawful for you to have your brother's wife." John the Baptist was executed for saying Herod sinned. Like the question on paying the Roman tax, this is an effort to get Jesus killed. Jesus outsmarts them by asking, "What did Moses say?" When they answer, 'Moses allowed divorce', Jesus accuses them: "because of your hardness of heart." 'Moses allowed it,' Jesus says, 'because humans are sinful.' God's law allows it, but God's original intent is one man, one woman, for life. So we need to be clear, Jesus says that God allows divorce, but that is not the goal and remarriage is adultery.
Jesus looks to Genesis 2. When God declares "it is not good that the man is alone," it is a judgement on loneliness. The Creator addresses the man's isolation by creating a "helper." Some think this a derogatory term, but the Hebrew word (ezer) is used almost exclusively of God in the Bible, so it may imply that she will be like the divine presence for the man. Adam's flesh becomes two people, and marriage makes two people one flesh. Marriage, therefore, is connected to creation.
What about the adultery issue? First of all, remarriage is the issue, but Jesus teaches that fundamentally (Mt 5:28) adultery is a matter of the heart. It is produced by the passions within us, most notably lust and coveting. What this means is adultery is secretly at work in the heart of almost everyone. We are all adulterers. So the reason why Jesus calls remarriage adultery is because He speaks the truth, what else can it be called? Let's ponder the question.
In our church the couple is asked "Will you love, comfort, honor, keep one another in sickness and in health, forsake all others, be faithful as long as you live?" What does this mean? Shouldn't we just say "Maybe" if the words have no real meaning?
The couple declares to each other: "I take you...for better for worse, for richer for poorer, in sickness and in health, to love and to cherish, until parted by death." What does that mean? We say these words before God and other people, yet, in the US, the average first marriage lasts eight years, and close to half of marriages fail.
The effort to undo Christian civilization has included a focus on undermining the institution of marriage. It is working. The current marriage rate is at record lows and one third of Millenials will never marry. More and more couples opt to just live together, with society's blessing, but it is actually even less stable and worse for kids. And the human sexes (male and female) are replaced with Gender, the number of young people identifying as LGBTQ has dramatically increased the last five years and is now over 8%. Much of this is a function of hyper-individualism. Parents say that their child should choose what they are irrespective of biology. The individual "I," alone, decides what is right and true. Perhaps this is why God said, "It is not good for the man to be alone...."
What do you want Jesus to say about all this?
Do you want Jesus to reject Genesis 2?
Should He advocate for no fault divorce?
Should He bless same sex unions?
Should He embrace multiple new sexual identities?
Should Jesus say "do whatever makes you happy"?
I cannot speak for Jesus, but I can tell you what He did say: God made us male and female. God's intent is for sexual intercourse to occur in a marriage between one man, one woman committed for life. It turns out that arrangement is better for everyone.
I understand this is very difficult, but if we fail it is a sin. Sin means to miss the mark. We sin all the time, failing to love God and neighbor as we should. The contemporary church has dealt with sin by pretending it doesn't exist. We don't want people to feel guilt and shame. Good News! We do not need to excuse or minimize sin, because Jesus loves and forgives sinners. We can face the truth because He is merciful, and repentance is only possible when we face the truth and trust in His mercy. Now, we should not condemn other people. We should not over-focus on particular sins, but neither must we pretend that everything is okay because society says so. Hollywood is a lousy moral teacher and the popular media is no friend of Jesus.
I understand this is hard, and I am not minimizing the struggles we face. I have walked with people through the heartbreak of life. I know that one person can destroy a marriage. I have seen that sometimes people can't stay together and work it out. I understand that people aren't always wired to fit neatly into one man, one woman, forever. I know that a number of people find Jesus' teachings hurtful. These realities, however, support my belief that we are all hard-hearted. We are all broken, wounded, and sinful people living in an imperfect world. We all need to be saved. Good News, that's why Jesus came!
Most importantly, marriage is a sacrament--a sign of the union of Christ and His Church. Marriage is a sacrament of theosis: covenant love between a man and a woman reflects the salvation unity of God and humanity. Yes, we often do a lousy job of it. We sometimes fail, and our failures cause real damage to our children and to our society. Yes, we sin, but Jesus Christ redeems our failures and saves our children and our world. So let's be sorry for sin and failure and let's have hope in the power of Abba Father to save. Jesus tells us what marriage is, I do not believe we should tell Him He is wrong. Neither should we be ashamed and despair because of our failures. Rather we should pray with hope and even joy, "Lord Jesus, Son of God, have mercy on me a sinner." Over and over. And know that He does.