When we translate the Greek conjunction γάρ as "for," we sometimes obscure the connection between verses. When Jesus says that the Pharisees wouldn't even get into the kingdom of God, how does that relate to his prior assertion that every iota and stroke of the pen found in the law will be fulfilled in him?
One of the more challenging conjunctions is γάρ. We tend to think it always means “for” in the sense of introducing a reason, but γάρ is much more fluid than that, and the English “for” isn’t.
Granted, the first definition in BDAG is, “marker of cause or reason, for.” This is its primary gloss, but only one among three.