I believe there is some very important parts of this Chapter that needs to be considered.
I don't mean for it to be so long, but I truly believe it is important to think about what happened in the chapter.
First, Paul is speaking about an encounter with Peter and the Mainstream religion of that time.
Gal. 2:
12 For before that certain came from James, he did eat with the Gentiles: but when
they were come,
he withdrew and separated himself,
fearing them which
were of the circumcision.
This is speaking of the Pharisees which were the Mainstream preachers of that time. They were the ones that Claimed to be "children of God" but the Christ pointed out that they were actually serving the devil. Peter had witnessed them murdering the Christ and probably Stephen. They pushed a religion which still included Levitical Priesthood "Works of the Law" for cleansing of sins. They claimed to be following the Law of Moses, but Jesus said several times that they were not. Both Paul and Peter were part of this religion before the Christ came to them.
Paul has already told folks that these preachers were pushing their version of the Levitical Priesthood sacrificial "works of the law" for justification of sins, even after they had shown that this Christ was the prophesied Messiah.
Rom. 2:
27 Where
is boasting then? It is excluded.
By what law?
of works? (Levitical Priesthood) Nay:
but by the law of faith.
28 Therefore we conclude that a man is justified by faith
without the deeds of the law. (No more sacrificial, ceremonial "works of the Law" given by God to the Levites for atonement of sins)
So when Peter feared these mainstream preachers and stop eating with the Gentiles Paul rebuked him.
14 But when I saw that they walked not uprightly according to the truth of the gospel, I said unto Peter before
them all, If thou, being a Jew, livest after the manner of Gentiles, (No Jewish religious traditions, no animal sacrifices, no Levite Priests) and not as do the Jews,
why compellest thou the Gentiles to live as do the Jews? (Compel the Gentiles to follow a religious tradition that the Christ said was from man and not from God)
16 Knowing that a man is not justified by the
works of the law, but by the faith of Jesus Christ, even we have believed in Jesus Christ, that we
might be justified (sins forgiven) by the faith of Christ, and not by the
works of the law (Levites performing sacrificial "deeds" of the Law) for by the
works of the law shall no flesh be justified.
There was only one "LAW" that was created for the justification of sins. It was a Levitical Priesthood given by God to the Levites which advocated for sins being cleansed by specific "works of the Law" that only a Levite could perform. The Christ had become the High Priest and had changed the Priesthood and took it over. Many of the Jews didn't "Believe" this and still continued in the "old" "obsolete" animal sacrifices and ceremonial "Works of the Law" for the cleansing of sins, or to make a person righteous. (See Heb. 7-10)
17 But if, while we seek to be justified by Christ,
we ourselves also are found sinners,
is therefore Christ the minister of sin?
God forbid.
18 For
if I build again the things
which I destroyed, (repentance)
I make myself a transgressor.
Paul is saying if he
transgresses the Commandments of God, (Law of Faith, Love God, Love your Neighbor, Honor Him) he "makes himself" once again, a sinner. And this reflects on the Christ who He claims to have Faith in. Is Christ the Minister of transgressing God's Commandments? God forbid.
19 For I
through the law (Law of faith) am dead
to the law, (Of Works)
that I might live unto God.
20 I am crucified with Christ: nevertheless I live; yet not I,
but Christ liveth in me: and the life
which I now live in the flesh I live by the
faith of the Son of God, ( Not by the old Levitical Priesthood ceremonies) who loved me,
and gave himself for me. (not the blood goats as the "LAW of works" prescribed)
21 I do not frustrate the grace of God: for if righteousness
come by the law, (The sprinkling of goats blood on the alter) then Christ is dead in vain.
So Paul will indeed be judged by his "DEEDS" "if I build again that which I destroyed" namely transgression of God's Commandments that he lived in as a Pharisee, he will be counted as a "transgressor" and would have need of repentance.
Like he said before.
Rom. 2:
9 Tribulation and anguish,
upon every soul of man
that doeth evil, of the
Jew first, and
also of the Gentile;
10 But glory, honour, and peace,
to every man that worketh good, to the
Jew first, and
also to the Gentile:
11 For there is no respect of persons with God.
Sorry so long, but we all have been so influenced by "the other voice" it's good to try and be thorough.
Great question