1. They must advance God, and study how to do him honour: "Give glory to the Lord your God, and not to your idols, not to other gods. Give him glory by confessing your sins, owning yourselves guilty before him, and accepting the punishment of your iniquity, v. 16. Give him glory by a sincere repentance and reformation." Then and not till then, we begin to live as we should, and to some good purpose, when we begin to give glory to the Lord our God, to make his honour our chief end and to seek it accordingly. "Do this quickly, while your space to repent is continued to you; before he cause darkness, before you will see no way of escaping." Note, Darkness will be the portion of those that will not repent to give glory to God. When those that by the fourth vial were scorched with heat repented not, to give glory to God, the next vial filled them with darkness, Rev. xvi. 9, 10. The aggravation of the darkness here threatened is, (1.) That their attempts to escape shall hasten their ruin: Their feet shall stumble when they are making all the haste they can over the dark mountains, and they shall fall, and be unable to get up again. Note, Those that think to out-run the judgments of God will find their road impassable; let them make the best of their way, they can make nothing of it, the judgments that pursue them will overtake them; their way is dark and slippery, Ps. xxxv. 6. And therefore, before it comes to that extremity, it is our wisdom to give glory to him, and so make our peace with him, to fly to his mercy, and then there will be no occasion to fly from his justice. (2.) That their hopes of a better state of things will be disappointed: While you look for light, for comfort and relief, he will turn it into the shadow of death, which is very dismal and terrible, and make it gross darkness, like that of Egypt, when Pharaoh continued to harden his heart, which was darkness that might be felt. The expectation of impenitent sinners perishes when they die and think to have it satisfied.