"Work hard to go through the narrow doorway." Jesus is speaking about the entrance to God's kingdom as if it were a small doorway to a house. Since Jesus is talking to a group, the "you" implied in this command is plural. (See: [[rc://en/ta/man/translate/figs-metaphor]] and [[rc://en/ta/man/translate/figs-you]])
# the narrow door
The fact that the door is narrow implies that it is difficult to go through it. Translate it in a way to keep this restrictive meaning. (See: [[rc://en/ta/man/translate/figs-explicit]])
It is implied that they will not be able to enter because of the difficulty of entering. The next verse explains the difficulty. (See: [[rc://en/ta/man/translate/figs-explicit]])