Consider two important truths in Psalm 31:19.
1. The goodness of the Lord
There is a peculiar goodness of God. That is, there is not only God’s general goodness that he shows to all people, making his sun rise on the evil and the good (Matthew 5:45), but also a peculiar goodness for “those who fear him.”
This goodness is abundant beyond measure. It is boundless. It lasts forever. It is all-encompassing. There is only goodness for those who fear him. Everything works together for their good. Even their pains are filled with profit (Romans 5:3–5).
But those who do not fear him receive a temporary goodness — a goodness that does not lead to repentance, but leads to worse destruction (Romans 2:4).
2. The fear of the Lord
The fear of the Lord is the fear of straying from him. Therefore it expresses itself in taking refuge in God. That’s why two conditions are mentioned in Psalm 31:19 — fearing the Lord and taking refuge in him.
They seem to be opposites. Fear seems to drive away and taking refuge seems to draw in. But when we see that this fear is a fear of not being drawn in, then they work together.
There is a real trembling for the saints. “Work out your salvation with fear and trembling” (Philippians 2:12). But it is the trembling one feels in the arms of a Father who has just plucked his child from the undertow of the ocean.