Verses with the word understandeth in the Old Testament (6 verses):

1 Chronicles 28:9
And thou, Solomon my son, know thou the God of thy father, and serve him with a perfect heart and with a willing mind: for the LORD searcheth all hearts, and understandeth all the imaginations of the thoughts: if thou seek him, he will be found of thee; but if thou forsake him, he will cast thee off for ever.

Job 28:23
God understandeth the way thereof, and he knoweth the place thereof.

Psalms 49:20
Man that is in honour, and understandeth not, is like the beasts that perish.

Proverbs 8:9
They are all plain to him that understandeth, and right to them that find knowledge.

Proverbs 14:6
A scorner seeketh wisdom, and findeth it not: but knowledge is easy unto him that understandeth.

Jeremiah 9:24
But let him that glorieth glory in this, that he understandeth and knoweth me, that I am the LORD which exercise lovingkindness, judgment, and righteousness, in the earth: for in these things I delight, saith the LORD.