Jesus tells the parable of the Pharisee and the tax collector, talks about divorce, blesses some children, then shows a rich man he has to love Jesus enough to sell everything to follow Him: Luke 18:9–14;; Mark 10:1–12; Matthew 19:1–12;; Mark 10:13–16; Matthew 19:13–15; Luke 18:15–17; Mark 10:17–31; Matthew 19:16–30; Luke 18:18–30
This is a hard teaching. It was then, and it is now. It can be summarised as remarriage after divorce = adultery (with exceptions).
Even though Moses allowed divorced, Jesus had to explain that divorce really wasn’t God’s plan A:
Matthew 19:8-9 Moses permitted divorce only as a concession to your hard hearts, but it was not what God had originally intended. And I tell you this, whoever divorces his wife and marries someone else commits adultery—unless his wife has been unfaithful.
And yes, it is a hard line. Even Jesus’ disciples baulked at the idea. It suggests that divorce was no less common or socially acceptable than it is now
Matthew 19:10 Jesus’ disciples then said to him, ‘If this is the case, it is better not to marry!’
And Jesus knew it was hard:
Matthew 19:12-12 Not everyone can accept this statement. Only those whom God helps. Some are born as eunuchs, some have been made eunuchs by others, and some choose not to marry for the sake of the Kingdom of Heaven. Let anyone accept this who can.