Galatians 3 - verses being 3, 16, and 26-29 - deals with the change in the doctrine of the physical bloodline from Abraham to Israel, that is, what is it which determines who is Israel?
The certain implication of these verses is that under the New Covenant belief in Christ and belief in his doctrines is what determines who is Israel.
"But after that faith is come, we are no longer under a schoolmaster.
26. For ye are all the children of God by faith in Christ Jesus.
27. For as many of you as have been baptized into Christ have put on Christ.
28. There is neither Jew nor Greek, there is neither bond nor free, there is neither male nor female: for ye are all one in Christ Jesus.
29. And if ye be Christ's, then are ye Abraham's seed, and heirs according to the promise." Galatians 3: 25-29
There is no physical, literal bloodline here which determines who is Israel, who are the children of God, who are the elect of God.
One of the tactics of the dialectic as an argument or quarrel against the truth of scripture is to try to distract attention away from that truth in some way, sometimes by a focus on some other scripture which is not relevant to the Truth of another scripture which is the issue. The issue with the verses above, including verse 3 and verse 16 of Galatians 3 is whether in the New Covenant there is still the physical bloodline from Abraham which determines who are the children of God, who are the chosen people.
The dialectic sets up an opposition. The scripture at issue can be seen as the thesis while the opposition or anti-thesis tries to overthrow that thesis and in the Hegelian dialectic there is an outcome which is called the synthesis, often a compromise.
The dialectic is seen in scripture. Satan used it on Eve in Genesis 3: 1-6. There is a form of it used by the Pharisees in a dialogue with Christ in John 8. "Then said Jesus to those Jews which believed on him, If ye continue in my word, then are ye my disciples indeed;
32. And ye shall know the truth, and the truth shall make you free.
33. They answered him, We be Abraham's seed, and were never in bondage to any man: how sayest thou, Ye shall be made free?" John 8: 31-33
"Then answered the Jews, and said unto him, Say we not well that thou art a Samaritan, and hast a devil?
49. Jesus answered, I have not a devil; but I honour my Father, and ye do dishonour me."
Jesus was teaching in John 8: 31-33, but the Pharisees did not understand and/or did not accept his teachings and the Pharisees started saying he was a Samaritan who was demon possessed. Thats a tactic of the dialectic, to try to change the focus of the debate away from what Christ was teaching - for example, that the truth can make you free of bondage to the many rules of the Pharisees to something else.
There is also a very brief mention of the early Greek philosophy of the dialectic in I Timothy 6: 20, which in seen in the Greek, but not made explicit in the English translations.
"O Timothy, keep that which is committed to thy trust, avoiding profane and vain babblings, and oppositions of science falsely so called:"
ω τιμοθεε την παρακαταθηκην φυλαξον εκτρεπομενος τας βεβηλους κενοφωνιας και αντιθεσεις της ψευδωνυμου γνωσεως
αντιθεσεις, or antitheseis, anti-thesis, is Strong's number 477, "opposition,i.e., conflict of theories."
Other Greek words mean oppose or opposition, such as Strong's 475, antidiaithemai, to set oneself opposite.
There is also Strong's number 498, antitassomai, to range oneself against, to oppose.
And there is Strong's 480, antikeimai, to lie opposite, be adversive, adversary, be contrary, oppose.
Antitheseis, used in I Timothy 6: 20, is a term used by the Greek philosophers before Christ who were into the dialectic as a way of making an argument.
Another translation of γνωσεως, gnoseos, is knowledge, which fits in with the Greek word αντιθεσεις, or anti-thesis.
But you might ask, how did a word from the Hegelian dialectic get in Paul's writing in the First Century? Hegel lived from 1770 to 1831. The answer is that in Greek philosophy before the time of Christ, there was a school of philosophy on the dialectic. Paul was educated and could very well have known about that Greek philosophical school and its terminology.
Paul uses αντιθεσεις, or anti-thesis, in I Timothy 6: 20, which is part of the terminology of the early Greek philosophical school on the dialectic. But Paul does not use διαλεκτική, or dialectic.
https://en.wikipedia.org/wiki/Dialectic
"Dialectic (also dialectics and the dialectical method), from Ancient Greek διαλεκτική, is a method of argument.....The word dialectic originated in ancient Greece, and was made popular by Plato in the Socratic dialogues."
"In classical philosophy, dialectic (Greek: διαλεκτική) is a form of reasoning based upon dialogue of arguments and counter-arguments, advocating propositions (theses) and counter-propositions (antitheses)."
"Aristotle said that it was the pre-Socratic philosopher Zeno of Elea who invented dialectic, of which the dialogues of Plato are the examples of the Socratic dialectical method."