1 Samuel 28:2

And David said to Achish, You will see now what your servant will do. And Achish said to David, Then I will make you keeper of my head for ever.

1 Samuel 27:10

And every time Achish said, Where have you been fighting today? David said, Against the South of Judah and the South of the Jerahmeelites and the South of the Kenites.

2 Samuel 16:16-19

Then Hushai the Archite, David's friend, came to Absalom and said, Long life to the king, long life to the king!

Romans 12:9

Let love be without deceit. Be haters of what is evil; keep your minds fixed on what is good.

Treasury of Scripture Knowledge

Summary

And David said to Achish, Surely thou shalt know what thy servant can do. And Achish said to David, Therefore will I make thee keeper of mine head for ever.

Bible References

Surely

1 Samuel 27:10
And every time Achish said, Where have you been fighting today? David said, Against the South of Judah and the South of the Jerahmeelites and the South of the Kenites.
2 Samuel 16:16
Then Hushai the Archite, David's friend, came to Absalom and said, Long life to the king, long life to the king!
Romans 12:9
Let love be without deceit. Be haters of what is evil; keep your minds fixed on what is good.

Basic English, produced by Mr C. K. Ogden of the Orthological Institute - public domain