Verses with the word diminish in the Old Testament (8 verses):

Exodus 5:8
And the tale of the bricks, which they did make heretofore, ye shall lay upon them; ye shall not diminish ought thereof: for they be idle; therefore they cry, saying, Let us go and sacrifice to our God.

Exodus 21:10
If he take him another wife; her food, her raiment, and her duty of marriage, shall he not diminish.

Leviticus 25:16
According to the multitude of years thou shalt increase the price thereof, and according to the fewness of years thou shalt diminish the price of it: for according to the number of the years of the fruits doth he sell unto thee.

Deuteronomy 4:2
Ye shall not add unto the word which I command you, neither shall ye diminish ought from it, that ye may keep the commandments of the LORD your God which I command you.

Deuteronomy 12:32
What thing soever I command you, observe to do it: thou shalt not add thereto, nor diminish from it.

Jeremiah 26:2
Thus saith the LORD; Stand in the court of the LORD's house, and speak unto all the cities of Judah, which come to worship in the LORD's house, all the words that I command thee to speak unto them; diminish not a word:

Ezekiel 5:11
Wherefore, as I live, saith the Lord GOD; Surely, because thou hast defiled my sanctuary with all thy detestable things, and with all thine abominations, therefore will I also diminish thee; neither shall mine eye spare, neither will I have any pity.

Ezekiel 29:15
It shall be the basest of the kingdoms; neither shall it exalt itself any more above the nations: for I will diminish them, that they shall no more rule over the nations.