Who is the fool according to the Bible?

In Matthew 7:26-27, the fool is portrayed as someone who hears the sayings of Christ yet does not heed them, likening them to a man building his house on sand. This metaphor highlights the futility and danger of relying on one's own actions or beliefs for salvation instead of placing faith in Christ. The fool, therefore, is anyone who believes they can achieve righteousness through their own merit rather than through the grace of God. Those who trust in their works stand in jeopardy of receiving the rod of God's justice instead of the comfort found in Christ's atoning sacrifice.