Albert Barnes Commentary 1 Samuel 14:1

"Now it fell upon a day, that Jonathan the son of Saul said unto the young man that bare his armor, Come, and let us go over to the Philistines` garrison, that is on yonder side. But he told not his father." — 1 Samuel 14:1 (ASV)

The word "Now" should rather be translated as "and," since this verse is immediately dependent upon the preceding one. When Jonathan saw the garrison come out again and again in defiance of the armies of the living God, he finally, upon a day, determined to attack them.