Wisdom can be defined as "applied knowledge." It's not enough to just know something; you need to know what to do with that information. On a spiritual level, the Bible teaches us "Wisdom is the
principal thing; therefore, get wisdom. And in all your getting get understanding" (Proverbs 4:7 NKJV). That means the first thing we should seek after is wisdom.
Further, wisdom is not just a concept, but also a person. "Wisdom shouts in the streets. She cries out in the public square. She calls to the crowds along the main street, to those gathered in front of the city gate" (Proverbs 1:20-21 NLT).
What is Wisdom saying? That it is foolish to say - verbally or non-verbally, through action or inaction - that there is no God.