1 Corinthians 9:20

And to the Jews I became as a Jew, that I might gain the Jews; that is, to those, who are under the law, as under the law, that I might gain those who are under the law:

Acts 16:3

wherefore Paul was desirous that he should go forth with him, and took and circumcised him because of the Jews that were in those parts; for they all knew that his father was a Greek.

Acts 21:20-26

And when they heard it, they glorified the Lord, and said to him, Thou seest, brother, how many myriads there are of the believing Jews, and they are all zealous for the law.

Acts 17:2-3

And according to his custom Paul went in among them, and for three sabbath-days discoursed to them from the scriptures;

Acts 18:18

And after Paul had staid there yet a considerable time, he took leave of the brethren, and sailed from thence to Syria, and with him Priscilla and Aquila, after he had shaved his head at Cenchrea; for he had a vow.

Romans 3:19

it saith to those under the law: that every mouth may be stopped, and all the world obnoxious to the justice of God.

Romans 6:14-15

For sin shall have no power over you, inasmuch as ye are not under the law, but under grace.

Romans 11:14

I extol my office, that if possible I may excite to emulation my brethren according to the flesh, and may save some of them:

Galatians 4:5

that He might redeem those that were under the law, that we might receive the adoption of sons.

Galatians 4:21

Tell me, you that are so desirous to be under the law, do ye not hear the law?

Galatians 5:18

But if ye be led by the Spirit, ye are not under the law.

Treasury of Scripture Knowledge

Summary

And unto the Jews I became as a Jew, that I might gain the Jews; to them that are under the law, as under the law, that I might gain them that are under the law;

Bible References

Unto

Acts 16:3
wherefore Paul was desirous that he should go forth with him, and took and circumcised him because of the Jews that were in those parts; for they all knew that his father was a Greek.
Acts 17:2
And according to his custom Paul went in among them, and for three sabbath-days discoursed to them from the scriptures;
Acts 18:18
And after Paul had staid there yet a considerable time, he took leave of the brethren, and sailed from thence to Syria, and with him Priscilla and Aquila, after he had shaved his head at Cenchrea; for he had a vow.
Acts 21:20
And when they heard it, they glorified the Lord, and said to him, Thou seest, brother, how many myriads there are of the believing Jews, and they are all zealous for the law.

Are under

Romans 3:19
it saith to those under the law: that every mouth may be stopped, and all the world obnoxious to the justice of God.
Romans 6:14
For sin shall have no power over you, inasmuch as ye are not under the law, but under grace.
Galatians 4:5
that He might redeem those that were under the law, that we might receive the adoption of sons.
Galatians 5:18
But if ye be led by the Spirit, ye are not under the law.

General references

Luke 11:37
And as He spake, a certain pharisee asked Him to dine with him: and He went in and sat down at table.
Romans 15:2
but let every one of us please our neighbor for his good, to his edification.
1 Corinthians 10:33
Even as I also endeavour to please all men in all things, not seeking my own advantage, but that of many, that they may be saved.
Galatians 2:3
But even Titus, who was with me, being a Greek, was not compelled to be circumcised;