Soon after calling the 12, Jesus teaches them with a new law on a new mountain, like Moses.
He describes the traits of those in His kingdom: poor in spirit, hungering for righteousness, salt and light. His new law doesn't undo the old, but takes in further: beyond murder to anger, beyond adultery to lust, beyond regulating divorce to restricting the reasons for it, beyond hating enemies to loving them, beyond doing good works for show to doing them for God. Don't run after money, clothes or food; seek God's kingdom first. As often as you judge, you will be judged, and with the same measure. Doing to others what you'd want them to do to you sums up the whole Law and Prophets. Notice, it is doing from the heart, not just hearing or even doing in God's name. Many think they're in the kingdom, but are not.