There's a whole lot of very difficult teachings in the Bible that, at quick glance, seem not to be that difficult. That is until the command is against you: "Love your enemies; bless those who persecute you; do not resist evil." Easy to say until someone's plucking your eyeballs out.
"Adulterers will be cast into the lake of fire, and remarriage after divorce is adultery." Pretty easy to chew on that and swallow when you're raised with it in your entire life, and you're a million miles away from that ever being a possibility in your life.