Jesus, more than anyone else in human history, speaks about the things of God with authority, knowledge, and credibility.
Jesus explained what the kingdom of heaven is like at length. He sure sounded like he knew what he was talking about. But that was not the only time when his knowledge was plain to see.
Anyone who speaks to a Jewish crowd, to people who are followers of Moses, and claims to surpass the Law of Moses -- he had better have something good to follow through on that claim. And Jesus did. They believed him and considered that there might be a more excellent way.
Anyone who speaks to people who hope for a resurrection -- or debate the reality of the resurrection -- and claims to know exactly how the Last Day will happen, had better have something good to say. Again, he did. He gave a detailed description of the Last Day that is at the same time believable, just, and desirable. Hearing his teaching doesn't inspire arguments about its justness; its justice is self-evident. What it inspires is awe. The people who first heard him noticed. They were amazed at his teachings, because he spoke as one having authority.
In the beatitudes, some of the blessings Jesus proclaimed were bold promises: the pure in heart shall see God; the meek shall inherit the earth. Those who hunger and thirst for righteousness will be satisfied; those who mourn will be comforted. Anyone who claims to know the heart of God, and to know what God will do in the future, better have something good. And Jesus did. The blessings meet and even exceed our sense of rightness, that this is how things should be. God's goodness surpasses our hopes, and restores our confidence enough to hope.
Many people go to religion or spirituality looking for a religious experience; the surest way I know to have a religious experience is to read what Jesus said.