Paul, on occasion, limited his freedom for the sake of his kinsmen, the Jews. Though free from the Law, he placed himself under its demands to minister to Jews. Limiting one's freedom is an individual choice. In an age of grace, there is no place for legalism. Paul further explained the Law's purpose.
Law is unnecessary for the righteous.
One can make a reasonably accurate estimation of the righteousness of a society by the number and range of its laws. Generally speaking, the more laws a society has, the more unrighteous that society. The writer to the Hebrews explained that righteousness did not come through the Mosaic Law because the priesthood of the Messiah came out of the order of Melchizedek, not out of Aaron. The Aaronic priesthood's basis was the Mosaic Law. It could not effect perfection or righteousness.