What is the meaning of Acts 23:7-9?

7 And when he had so said, there arose a dissension between the Pharisees and the Sadducees: and the multitude was divided. 8 For the Sadducees say that there is no resurrection, neither angel, nor spirit: but the Pharisees confess both. 9 And there arose a great cry: and the scribes that were of the Pharisees’ part arose, and strove, saying, We find no evil in this man: but if a spirit or an angel hath spoken to him, let us not fight against God. (Acts 23:7-9 KJV)

William Burkitt’s Commentary

Observe here, 1. How sad a state, and how bad a condition, was the Jewish church now in, when in the Sanhedrin, or great council, men had power and authority, who believed in no life but this; and what hypocrites were the Pharisees, who could thus incorporate and embody with damnable heretics, the Sadducees, and yet at the same time hated and persecuted the Christians. The Sadducees were so far from believing that there was any spirit that they blasphemously maintained that God himself was not spiritual, but only a corporeal being. When men sin with obstinacy against supernatural light, God justly withdraws from them even the natural light and allows them to fall from one degree of error to another.

Observe, 2. How partiality will change men’s judgments, according to the interest of a party or faction. The Pharisees were bitter enemies of the apostle; but, because he owned himself of their sect, they instantly took side with him, and cry,  We find no fault with him. The feuds about religion are commonly the sharpest feuds; men are more fond of the notions of their brains than they are of the issue of their bodies.  Odia Religiosorum sunt acerbissima; “Religious hates are hottest.”

Observe, 3. How the dissensions of God’s adversaries oft-times become the deliverance of God’s servants. Thus here the Pharisees and Sadducees quarrel about the resurrection: the Pharisees justify Paul, and tell them that oppose him, “They are in danger of fighting against God.” Thus God when he pleases, can find or make patrons of his people, and raise up friends from amongst his very enemies to defend his cause.