Ans. To the unbelieving Jews and their proselytes, I grant he did. But we read not that he did it to any new testament church on that day: nor did he celebrate the instituted worship of Christ in the churches on that day. For Paul, who had before cast out the ministration of death, as that which had no glory, would not now take thereof any part for new testament instituted worship; for he knew that that would veil the heart, and blind the mind from that, which yet instituted worship was ordained to discover.
He preached then on the seventh day sabbath, of a divine and crafty love to the salvation of the unbelieving Jews.
I say, he preached now on that day to them and their proselytes, because that day was theirs by their estimation. He did it, I say, of great love to their souls, that if possible, he might save some of them.
Wherefore, if you observe, you shall still find, that where it is said that he preached on that day, it was to that people, not to the churches of Christ. See Acts 9:20, 13:14-16, 16:13, 17:1-3, 18:4.
Thus, though he had put away the sanction of that day as to himself, and had left the Christians that were weak to their liberty as to conscience to it, yet he takes occasion upon it to preach to the Jews that still were wedded to it, the faith, that they might be saved by grace.
Paul did also many other things that were Jewish and ceremonial, for which he had, as then, no conscience at all, as to any sanction that he believed was in them.
As his circumcising of Timothy (Acts 16:1-3).
His shaving of his head (Acts 18:18).
His submitting to Jewish purifications (Acts 21:24-26).
His acknowledging of himself a Pharisee (chap. 23:6).