The book of Matthew (chapters 5 through 7) records Jesus’ words in a well-known series of chapters known as the Sermon on the Mount.
Jesus went up on a small hill and began preaching, and what he said amazed the assembled crowd who heard it.
It amazes us, still.
Jesus’ teachings were both shocking and clear to those who heard them; startling statements meant to both spiritually awaken and challenge us to action.
He started by teaching about the character that God wishes us to have. In these “beatitudes,” Jesus assures us that God sends blessings of comfort, hope, healing, love, and strength, and that God expects us to share these blessings with others.
Jesus calls us to become both salt and light – spiritually enriching the world by being great moral examples to it - and says that we can do this by humbly performing righteous deeds.
Our attitudes towards oaths, marriage and even our dealings with our enemies, he says, ought to be guided by extremely high ideals, not by shallow obedience alone.
But just because this challenging sermon IS so challenging, some scholars and churchmen throughout history have questioned whether it REALLY should be taken seriously by us at all.
For example, some have claimed that Jesus' teachings in this Sermon were not meant to be followed, but instead, his intention was to merely show us what we COULD NEVER accomplish, because all human beings are too corrupted to obey his teachings.
When Jesus said we should avoid even thinking of committing adultery - an act that is one of God's Ten Commandments to Moses - they claim that we couldn't possibly avoid thinking of such a thing. Therefore, they assert, Jesus was teaching that human beings couldn't possibly do what he was asking.
But to believe this would make Jesus a mean-spirited, cynical teacher. And indeed, most who believe this way don't see him as much of a teacher at all, but as someone who’s just mocking (or "convicting") us by spouting high ideals that are beyond our ability to obey.
This kind of teacher would seem mean and sadistic in a classroom, and insane standing on a hill claiming to be a religious Teacher from God.
A teacher who would mock us by teaching what we cannot follow (and then teach that we'd be punished by God if we didn't!) would be the worst of all teachers, and certainly not a prophet sent from God.
Of course, Jesus, our God-anointed Master, never said his teachings were impossible to follow, so we can reject this interpretation. He said, "follow me," and "obey my teachings," and "let your light shine before others."
It's reasonable to take Jesus at his word, that he wants us to strive for even higher ideals than simply not cheating on one's spouse. He calls us to purify even our thoughts, not just our outward deeds.
This is consistent with his other teachings, in which he condemns the Judean religious teachers known as the Pharisees for having an outward appearance of goodness, like "a whitewashed tomb" he said, but inside, their minds were full of corruption and evil. This imagery clearly illustrates what he means by his teachings on the Mount, and elsewhere.
We start the process of committing a sin by thinking about it, and dwelling upon it. Jesus knew this, and warned us to guard our thoughts just as we are to guard our actions.
"Out of the good treasure of our hearts," put there by our thoughts, come goodness in the form of good works that serve others and please God.
We can be assured that Jesus meant what he taught at face value, and when he says that we can become morally and spiritually complete, and that we can do all the he did during his ministry, we can rest easy knowing that he is not lying to us or mocking us.