It seems as though that no matter how many verses refer to the intent of Deut. 4:2, studiers of the bible still seem to overlook that it is referring to the Torah (Old Testament), not of the New Testament. The New Testament was not written when Our Heavenly Father commanded that no one should add to His word.
Deuteronomy 4:2 “You shall not add to the word which I command you, nor take anything from it”.
Deuteronomy 12:32 “Whatever I command you, you shall be careful to do; you shall not add to nor take away from it.”
Joshua 1:7 Only be strong and very courageous, that you observe to do all the law (Strong’s 8451*) which Moses My servant commanded you; do not turn from it to the right or to the left, so that you may have success wherever you go”. (*towrah or torah; this Heb. noun comes from 3384. The meaning is instruction, doctrine, a precept, a statute, divine law, collective laws, teaching, the Five Books of Moses.)
The reason God is so adamant on this is because “The entirety of Your word is truth” (Psalms 119: 160).
“Do not add to His words, lest He reprove you, and you proved a liar.” Proverbs 30:6.
Proverbs 30:5-6: “Every word of God is pure; he is a shield to those who put their trust in Him.”
False teachers do not want to submit to its original intent, so they do not seek what Scripture actually (exegesis) means, instead, they conform it to what they want it to mean (isogesis).
This is why Paul admonishes us in 1 Corinthians 4:6: “not to think beyond what is written”. What was written then? The Torah. So, in other words, Paul is saying to not think beyond what is written in the Torah. When you add words to Torah it is as if you are really taking away from Scripture.
The NT reminds us and makes reference of God’s commandment in the Torah – “For I testify unto every man that hears, if any man shall add unto these things, God shall add unto him the plagues that are written in the Book (Strong’s 976**): And if any man shall take away from the words of this prophecy, God shall take away his part from the tree of life, and out of the holy city, and from the things which are written in this book.” Revelation 22:18-19. (**Biblos; Edyptian papyrus from which paper was made, a book, roll, volume, a sheet or a scroll)
Therefore, it is a requirement that the Torah should be kept just as it was given – nothing should be added afterward to it and nothing should be taken out of it; we should submit to it as to the inviolable word of God. Not by omissions only, but by additions also, is the commandment weakened. In light of this and Jesus’ Jewish heritage and how his thinking was shaped, in Matthew 5:17, Jesus (Heb. Yeshua) said “I did not come to abolish the law or the prophets, but to fulfill***. (Strong’s 4137) He did not come to end the old covenant but to glorify it- you cannot end something that God said was perpetual. (***Greek, Pleroo: thoroughly complete, accomplish, perform fully, to fill up as a net with fish- Matt 13:48, as a house with perfumed smell- John 12:3.)
Jesus came to point us back to the Torah in his obedience to Deut. 6:5-7 – “And you shall love the Lord your God with all your heart and with all your soul and with all your might. And these words which I am commanding you today, shall be on your heart; and you shall teach them diligently to your sons and shall talk of them when you sit in your house and when you walk by the way and when you lie down and when you rise up.”
With Jesus as an example of obedience to the instructions of HaShem, he dedicated his life to enforce and teach it. This is why Jesus again and again quoted the Torah.
Addtionally, for example, in Matthew 10:10 and Luke 10:7. Who or what is Paul quoting? He is quoting Moses. Why? Because Jesus quoted Moses. Therefore, we can easily reason and know that the first century church considered the writings of Moses (The Torah) to be God’s Word. The early church viewed the Old Testament to be “the Bible”. Mind you, during the early church the Torah and Prophets were not yet named The Old Testament, so God’s Word and Scripture was synonymous with Torah and the Prophets, as shown Luke 24:22. All too often we are taught erroneously that when ‘God’s Word’ is mentioned in the New Testament, they are referring to the NT. No! It wasn’t written yet. Jesus himself only referred to the Torah and the Prophets.
Prior to the canon which re-named The Torah and Prophets ‘The Old Testament’, God’s Word was referenced as the Tanakh, which is an acronym for the 3-part division of the Hebrew scripture, the Torah (The Law), the Nebuim (The Prophets) and the Kethubim (The Writings). Though the term Tanakh is more recent, the designations of the divisions of Hebrew scripture existed before the New Testament era.