2. Can Paul be blameless? (Philippians 3:6)
Pentecost is a Jewish holiday instituted by God at Sinai. You can read about it in Leviticus 23:15-22. It is known as the Day of Pentecost because it comes exactly fifty days after the Passover. It is also known as the Feast of Weeks, because it comes exactly seven weeks after the Feast of Firstfruits. The famous scene in Acts 2 in which Peter preached the first public gospel sermon and the Holy Spirit was poured out on the apostles occurred on the Day of Pentecost. This was significant for two reasons. First, there were Jews from all over the Roman world in Jerusalem for the feast. It was not an accident that the first gospel sermon was preached to the Jews when they had come from all over the world. This was very significant to the eventual spread of Christianity. Another reason for the giving of the Spirit and of the gospel to come on the Day of Pentecost is because there is prophetic implication. The Feast of Pentecost was the main harvest festival for the Jews. God used this as a foreshadow of the New Testament harvest. The harvest of souls for eternal life began at Pentecost in Jerusalem.
As for Philippians 3:6, I believe Paul is using a literary device known as hyperbole. Hyperbole is when a person purposefully uses exaggeration to make a point. Paul was not faultless, of course, but when it came to legalistically applying the law, he was just about the most righteous (and legalistic) of all the Jews. Someone says to you, "how do you feel?" You feel so good, you say "perfect." This is hyperbole. A parent tells their kid, "I told you a million times, clean up you room." This is hyperbole. I believe Paul is purposefully overstating himself to make a point. To paraphrase, "If anyone thought himself righteous because of his level of obedience to the law, it was me."
John Oakes, PhD