Deuteronomy 12:32

All of the things that I [am] commanding you, {you must diligently observe}; you shall not add to it, and you shall not take away from it."

Deuteronomy 4:2

You must not add to the word that I [am] commanding you, and you shall not take away from it [in order] to keep the commands of Yahweh your God that I [am] commanding you [to observe].

Joshua 1:7

Only be strong and very courageous {to observe diligently the whole law} that Moses my servant commanded you. Do not turn aside from it, [to] the right or left, so that you may succeed {wherever you go}.

Proverbs 30:6

Do not add to his words lest he rebuke you and you be found a liar.

Revelation 22:18-19

I testify to everyone who hears the words of the prophecy of this book: if anyone adds to them, God will add to him the plagues written in this book.

Deuteronomy 13:18

if you listen to the voice of Yahweh your God, to keep all [of] his commandments that I [am] commanding [to] you {today} [so as] to do the right [thing] in the eyes of Yahweh your God."

Matthew 28:20

teaching them to observe everything I have commanded you, and behold, I am with you all the days until the end of the age."

Treasury of Scripture Knowledge

Summary

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

Bible References

Thou shalt not

Deuteronomy 4:2
You must not add to the word that I [am] commanding you, and you shall not take away from it [in order] to keep the commands of Yahweh your God that I [am] commanding you [to observe].
Deuteronomy 13:18
if you listen to the voice of Yahweh your God, to keep all [of] his commandments that I [am] commanding [to] you {today} [so as] to do the right [thing] in the eyes of Yahweh your God."
Joshua 1:7
Only be strong and very courageous {to observe diligently the whole law} that Moses my servant commanded you. Do not turn aside from it, [to] the right or left, so that you may succeed {wherever you go}.
Proverbs 30:6
Do not add to his words lest he rebuke you and you be found a liar.
Matthew 28:20
teaching them to observe everything I have commanded you, and behold, I am with you all the days until the end of the age."
Revelation 22:18
I testify to everyone who hears the words of the prophecy of this book: if anyone adds to them, God will add to him the plagues written in this book.

General references

Genesis 6:22
And Noah did according to all that God commanded him; thus he did.
Genesis 21:4
And Abraham circumcised Isaac his son [when he was] eight days old, as God had commanded him.
Leviticus 8:4
So Moses did [just] as Yahweh commanded him, and the community gathered by the entrance to the tent of assembly.
Numbers 1:54
And the {Israelites} did thus; they did everything that Yahweh commanded Moses.
Deuteronomy 1:18
And so I instructed you at that time [concerning] all [of] the things that you should do.
Deuteronomy 4:2
You must not add to the word that I [am] commanding you, and you shall not take away from it [in order] to keep the commands of Yahweh your God that I [am] commanding you [to observe].
Deuteronomy 11:32
and you must diligently {observe} all the rules and the regulations that I [am] setting {before you} {today}."
Psalm 119:4
You have commanded your precepts, that [we] should keep [them] diligently.