No, the Bible does not say that God works in mysterious ways. However, it does say that His ways are higher than our ways (Isaiah 55:9) and that He often works in ways that we cannot understand or see (Proverbs 16:33). While we may not always be able to comprehend how or why God is working in a particular situation, we can trust that He is always good and His purposes are always for our benefit (Jeremiah 29:11). Ultimately, even when we don't understand what God is doing, we can have confidence that He is still in control and His plans will ultimately prevail (Proverbs 19:21).