1 Samuel 20:17 - Ellicott's Commentary On The Whole Bible

And Jonathan caused David to swear again. — Throughout this touching interview it is the prince who appears as the suppliant for the outlaw’s ruture kind offices. Jonathan — looking forward with absolute certainty to the day when his persecuted friend would be on the throne, and he in his grave — dreaded for his own fatherless children the fate which too probably awaited them, it having been in all ages a common custom in the East, when the dynasty was violently changed, to put to death the children and near relations of the former king.