Though the grace of being made in His Image was sufficient to give them knowledge of God the Word and, through Him, of the Father, God knew human weakness and also made provision for their neglect. If they failed to know God for themselves, they could come to know the Maker through the works of creation.
But as human neglect gradually grew worse, God again provided for this weakness by sending a law and prophets familiar to them. Even if they were reluctant to look up to heaven and know the Maker, they could receive instruction from those near at hand. For people can learn more directly from other people about higher things.
They could have looked up at the vastness of heaven, considered the harmony of creation, and come to know its Ruler, the Word of the Father. By His providence over all things, He makes the Father known to everyone; and for this purpose He moves all things, so that through Him everyone may know God.
Or, if they were reluctant to do this, they could meet with holy men and through them learn to know God, the Maker of all things, the Father of Christ, and to recognize that the worship of idols is godlessness and full of all impiety.
They could also have known the law, ceased from every lawless act, and lived a life of virtue. For the law was not for the Jews alone, nor were the prophets sent only for their sake. Although the prophets were sent to the Jews and were persecuted by the Jews, they were a sacred school for the whole world, teaching the knowledge of God and how the soul should live.
Although God’s goodness and love for humanity were so great, human beings were overcome by the pleasures of the moment and by the illusions and deceptions of demons. They did not look up toward the truth, but filled themselves with still more evils and sins, until their conduct made them seem irrational rather than rational.