Mystery

On the surface, verses 10-12 seem to be teaching that Jesus is intentionally tricky and vague to prevent the wrong people from understanding his teachings.

That isn't consistent with the teaching that Paul writes in 1 Timothy 2:3-4.  God wants everyone to be saved.

I think that this must be a tactical statement of some sort.  Jesus is sharing strategy with his disciples.

You don't give your adversaries too much of your game plan until it suits your purposes.  If God wants as many people as possible to join his family, but some people will use this information to harm the family, then the only responsible thing to do is withhold complete information.

I'm not particularly satisfied with this initial interpretation.  I'd like to explore some commentaries tomorrow to see how other Christians have addressed this passage.