The ways of the human heart and mind are many under every and all circumstances. Multiply that by many people. Try to comprehend the meaning of all that is done on earth. See all that God has done and comprehend it. Comprehension is impossible. That is what the Teacher, the author of this book is saying in these verses.
Deut. 29:29 says, “The secret things belong to the Lord our God, but the things revealed belong to us and to our children forever, that we may follow all his words.” This is similar to the Teacher’s conclusion in chapter 12.
Why then stop all work and leisure to consider the word of God? Why get up extra early in the morning to comprehend something from the Bible? These words are life. Where else can I go to find life? I will not comprehend the meaning of all and everything and that is fine with me. For what I seek is to spend time with me Father and receive from him life.