1 Samuel 20:17

Jonathan caused David to swear again. So strong was his conviction in David's future kingdom, and his wish that there should be an unbroken bond of love between the two families, that he makes David solemnly repeat his promise. The Septuagint and Vulgate, by altering the vowels, read, "And Jonathan sware again to David." At first sight this interpretation seems most in accordance with the reason given for the renewal of the oath, namely, Jonathan's own love; but the Masoretic text agrees better with what has gone before, and with his wish that their covenant under no change of circumstances should be broken.