Deuteronomy 4:2
1 Now, Israel, pay attention to the statutes and ordinances I am about to teach you, so that you might live and go on to enter and take possession of the land that the Lord, the God of your ancestors, is giving you. 2 Do not add a thing to what I command you nor subtract from it, so that you may keep the commandments of the Lord your God that I am delivering to you. 3 You have witnessed what the Lord did at Baal Peor, how he eradicated from your midst everyone who followed Baal Peor. 4 But you who remained faithful to the Lord your God are still alive to this very day, every one of you.
Sirach 18:6
Ben Sira, Ecclesiasticus4 To none has he given power to proclaim his works; and who can search out his mighty deeds? 5 Who can measure his majestic power? And who can fully recount his mercies? 6 It is not possible to diminish or increase them, nor is it possible to fathom the wonders of the Lord. 7 When human beings have finished, they are just beginning, and when they stop, they are still perplexed. 8 What are human beings, and of what use are they? What is good in them, and what is evil?
Notes and References
"... The one fresh phrase in the verse is 'do not subtract a thing,' a phrase found also in Deuteronomy 4:2 and 13:1: it is a formula found generally in ancient Near Eastern legal and wisdom texts ... Similar phraseology is found in Proverbs 30:6; Ecclesiastes 3:14; Sirach 18:6; 42:21; and Revelation 22:18-19 ..."
Holladay, William Lee Jeremiah 2: A Commentary on the Book of the Prophet Jeremiah, Chapters 26-52 (p. 140) Fortress Press, 1989