There are two ideas here. The first part of the verse speaks of major errors of ignorance.
There are all kinds of small falls on the journey of life. I have no time for God, no time for divine things, no time for the word of God. I take a decision; I get married and perhaps my marriage may turn out to be a cause of great sorrow. Or I take some other major decision of life and it turns out to be an absolute disaster for me. Decisions taken in two or three moments can be lifelong disasters. How much we need the guidance of God, the Lord to be with us, that shrewdness and wisdom that comes from him in salvation.