Matthew was written at some point in the late first century, 1,900-plus years ago. The complier/author's goal was to present a selection of the sayings and doings of Jesus useful to the churches of the Jesus Movement. The author did not have us in mind. She wrote for his time, not ours. Understanding that we are not going to get any closer to the actual Jesus than the three synoptic gospels (Mark, Matthew, & Luke), we need to read them critically and even selectively. Not everything in there is helpful to us today.
Speaking personally, one of the things I find difficult is the dualism of the whole of the Bible, both testaments. We see that dualism in today's passages. There is a narrow gate and a broad one. There are healthy trees and fruit-less ones. There are those who will enter the Kingdom and those wicked people who will not. Wise individuals build on rock, stupid ones build on sand. There is good; there is evil. Nothing in between. Right - Wrong. The Kingdom - hell. Wisdom - Folly. Nothing in between. This is dualism, and dualism is a human ideology. Dualism is about building walls. Dualists deal with opposition through judgment, pointed debates, oppositional politics, and even violence "when necessary." Dualists do not compromise because compromise is a sin. They do not dialogue, because the "bad guys" have nothing to say that they want to hear. Their goal is victory, often enough at any price. Us vs. Them. That's all there is.
So far as I can see dualism, as a human ideology, is often the antithesis of the teachings and actions of Jesus. In his acceptance of the poor, he violated one of the fundamental dualisms of his day, the distinction between the wealthy/righteous and the poor/sinful. He took pity on and healed the sick—in a time when illness was understood to be a symptom of God's displeasure. He touched lepers. He called a "sinful" tax collector to be one of his inner circle of disciples. He had a very different attitude about another one of the basic dualisms of his day, the distinction between ("superior") men and ("inferior") women. He even let women sit as his feet, a place normally reserved for male student/disciples.
Now, we take the point in these passages: there are wolves among the Jesus Movement sheep, advocating untenable moralities and theologies. False prophets were making Jesus out to be someone he wasn't. But we can't help but wonder who the compiler/author thought fell on the negative side of these dualities. Who were the bad guys who took the easy way out and built their houses on sand? Baptists, maybe. Catholics? Buddhists? LGBTQ'ers? Democrats?
My beef with dualism is that, for one thing, it simply doesn't reflect our human reality which is much more complex and where everything falls along continuums rather than at the two polar opposites. For another thing, it leads to prejudice, arrogance, a contentious spirit, judgmentalism, meanness, bigotry, and a whole lot of violence. The ultimate symbol of dualism is the Klan hanging black males for crimes they did not commit. It is the horrific ideologies that led to World War II.
Dualism was a fundamental, unquestioned, supposedly common sense ideology of the ancient world. It is hardly surprising that we find it in the Bible. That doesn't mean we have to buy into it. So far as I can see, at least, the Spirit of Christ transcended it. Amen.