What is permissible?

In tomorrow's Gospel reading Jesus is given a pop quiz by some Pharisees who ask, "Is it lawful for a man to divorce his wife?" Mark goes on to say

But Jesus said to them, “Because of your hardness of heart he wrote this commandment for you. But from the beginning of creation, ‘God made them male and female.’ ‘For this reason a man shall leave his father and mother and be joined to his wife, and the two shall become one flesh.’ So they are no longer two, but one flesh. Therefore what God has joined together, let no one separate.”

On this passage, Lindy Black's page says,

There were two schools of thought in Jesus' day concerning divorce, one liberal and one conservative. Rabbi Shammai taught that divorce was only permissible on the grounds of some sexual impropriety. His was the stricter view. Rabbi Hillel, on the other hand, had a more liberal view and taught that a man could divorce his wife for any reason. If she burned his breakfast, put too much salt on his food, showed disrespect to him, spoke disrespectfully of her husband's parents in his presence, spoke to a man on the street, or even let her hair down in public, he could divorce her. The view of Rabbi Hillel was the view that was popular in Jesus' day. So divorce was common in Palestine, and in this respect the setting was not unlike our own. Perhaps the most significant difference between their customs and ours lay in the status of the different genders. A man could divorce a woman on a whim, but a woman could not divorce a man for any cause. So the question becomes, "Just how high do you want to set the bar?" That was the question for Jesus. "Jesus, should a man divorce his wife for burned toast or only for adultery? Or do you set the bar somewhere in between? How high do you set the bar, Jesus?" Jesus responded the only way he could. He set the bar all the way up

It's not the only time Jesus is asked about the minimum, but refuses to take the bait, offering God's ideal instead. The same is true for the very limiting question, "who is my neighbor?" in response to which Jesus tells perhaps his best known parable, that of the Good Samaritan which sets a high bar as well. Perhaps even one's spouse could be the neighbor you are to love.