13 Now recollect, I pray, the cord pulled by the children, and breaking, and throwing on their backs those who pull it. Saul swore not once or twice, but several times. The people swore what was contrary, and strained in the opposite direction. Of necessity then it followed, that the oath must in any wise be broken through. For it were impossible that all these should keep their oaths. And now tell me not of the event of this transaction; but consider how many evils were springing from it; and how the devil from thence was preparing the tragedy and usurpation of Absalom.
For if the king had chosen to resist, and to proceed to the execution of his oath, the people would have been in array against him; and a grievous rebellion would have been set on foot. And again, if the son consulting his own safety had chosen to throw himself into the hands of the army, he would straightway have become a parricide. Do you see not, that rebellion, as well as child-murder, and parricide, and battle, and civil war, and slaughter, and blood, and dead bodies without number, are the consequences of one oath.
For if war had perchance broken out, Saul might have been slain, and Jonathan perchance too, and many of the soldiers would have been cut to pieces; and after all the keeping of the oath would not have been forwarded. So that it is not for you to consider that these events did not occur, but to mark this point, that it was the nature of the case to necessitate the occurrence of such things. However, the people prevailed. Come then, let us reckon up the perjuries that were the consequence.
The oath of Saul was first broken by his son; and again a second and a third, concerning the slaying of his son, by Saul himself. And the people seemed to have kept their oath. Yet if any one closely examines the matter, they too all became liable to the charge of perjury. For they compelled the father of Jonathan to perjure himself, by not surrendering the son to the father. Do you see how many persons one oath made obnoxious to perjury, willingly and unwillingly; how many evils it wrought, how many deaths it caused?
Source: Homilies on the Statues (New Advent)