I Samuel 20:42

42 Jonathan said to David, "Go in peace, for we have sworn friendship with each other in the name of the Lord, saying, 'The Lord is witness between you and me, and between your descendants and my descendants forever.'" Then David left, and Jonathan went back to the town.

42 And Jonathan said to David, Go in peace, for we two have taken an oath, in the name of the Lord, saying, The Lord will be between me and you, and between my seed and your seed for ever. Then David went away, and Jonathan went into the town.