The Sermon on the Mount
Jesus taught his disciples and the crowds the way of life in God's Kingdom: the Beatitudes, the Lord's Prayer, love for enemies, and the call to build on his words as on rock.
“Blessed are the poor in spirit, for theirs is the Kingdom of Heaven.”
Matthew 5:3 (World English Bible)
He said he came not to abolish the Law and the Prophets but to fulfill them (Matthew 5:17), and he pressed the commandments to the heart: anger as well as murder, lust as well as adultery. He taught his followers to pray “Our Father in heaven” (Matthew 6:9) and not to worry, but to seek first God's Kingdom and his righteousness (Matthew 6:33).
The crowds were astonished, because he taught as one who had authority, not like their scribes (Matthew 7:28–29). Luke records a similar sermon given on a level place.
Dating notes
Ussher: AD 31, soon after the choosing of the Twelve. Tradition places the sermon on the slope above Tabgha, near Capernaum. The month shown is estimated from the order of events in Ussher's harmony, so that events of the same year appear in sequence.