I think you're missing what I'm saying. It's mostly a
literary point. Here's the context:
"Enter by the narrow gate; for wide is the gate and broad is the way that leads to destruction, and there are many who go in by it. Because narrow is the gate and difficult is the way which leads to life, and there are few who find it."
If there are many ways and they don't necessarily lead to salvation but self-determined good things, then we're not talking about the way anymore. We're basically disagreeing with Jesus (the speaker).
That's anyone's prerogative, for sure, but a different metaphor is warranted at that point.
EDIT: Reading your other comments, it looks like the "blind men and the elephant" metaphor is your preference, which is fair, but it's contradictory to the "straight and narrow path" metaphor.
> Many seminary lectures have been filled by the intellectual quagmires that grow out of "let grace abound".
How a Christian should behave and how people get to heaven are two separate questions. Ephesians 2:8 and Galatians 2:16 are pretty straightforward. And there are plenty of other supporting verses besides.
But my point here is that people look at Christians and get caught up in the question of who are good people, which is really a secondary concern in Christian theology. It makes sense to assume it's a big deal to salvation theology since most world religions (and casual personal theologies besides) make achievement a central concern. But there's nothing in the Bible that says the worst Christian is better than the best atheist or anything. Or that Christians deserve any special consideration that agnostic people don't.