What does Proverbs 15:19 mean?

Thorns along a path not only look ugly, but also impede progress. Brushing against them causes pain and delays. Even worse would be attempting to walk through an entire row of thorn bushes. That's the imagery Solomon uses here. The "sluggard," or lazy person, is like someone expecting to make progress while walking directly through a bristly hedge. Like thorns on a path, laziness in a person's life reduces beauty and keeps him from accomplishing what is important. His life is full of obstructions, and it is going nowhere (Proverbs 10:4, 26; 12:27).

Scripture connects laziness to immorality; the contrasting attribute given here is "upright." This person's choice to work hard makes their life path clear, unobstructed, and straight. This is not a guarantee that life will be easy, or that all hard work will result in great success. The lesson is in the contrast: if the goal is to move forward, laziness is like walking through thorn bushes, while godliness and effort are like taking a smooth, flat highway (Psalm 16:11; 25:10; Proverbs 4:18; 15:21).

Like David, the "upright" person follows the path the Good Shepherd (John 10:11) takes. David testifies in Psalm 23, "He makes me lie down in green pastures. He leads me beside still waters. He restores my soul. He leads me in paths of righteousness for his name's sake" (Psalm 23:2–3). Along the paths of righteousness, the believer enjoys the direction God's Word gives him. Psalm 119:105 describes God's Word as lamp for each immediate step and a light for all of life's journey.