'Understanding' in the Bible

For it is written, I will destroy the wisdom of the wise, and will bring to nothing the understanding of the prudent.

For if I pray in an unknown tongue, my spirit prayeth, but my understanding is unfruitful.

What is it then? I will pray with the spirit, and I will pray with the understanding also: I will sing with the spirit, and I will sing with the understanding also.

Yet in the church I had rather speak five words with my understanding, that by my voice I might teach others also, than ten thousand words in an unknown tongue.

Brethren, be not children in understanding: howbeit in malice be ye children, but in understanding be men.