Today I saw a picture of corrugated cardboard such as is used for packaging. The wavy aspect of the cardboard actually contributes to greater strength and durability of the material. Similarly, though we might prefer a smooth life with no bumps, the metaphorical bumps and waves do actually strengthen us too. Many bible verses encourage us in this truth. James 1:2-4 tells us, "Consider it pure joy, my brothers and sisters, whenever you face trials of many kinds, because you know that the testing of your faith produces perseverance. Let perseverance finish its work so that you may be mature and complete, not lacking anything."
