Christ knows the past – what would have happened in the past if God had acted differently – and he knows the future – not only what will happen in the future, but what would happen in the future as a result of changes to the past; he knows all things. He speaks of such fearful things, such deep things.
There is an obvious application to those born into Christian families who do not come to faith. Because they have so much more light than those who have never heard the gospel, no matter how extreme the sin of those who are far off, they will be held more accountable. What great regrets they will have when they think of all the tenderness of a mother’s instruction from Scripture upon that mother’s knees, and all the orderly government of that family by a godly father, and yet they pushed it all away from them and chose to reject Christ.