John Gill Commentary 2 Samuel 1:5

"And David said unto the young man that told him, How knowest thou that Saul and Jonathan his son are dead?" — 2 Samuel 1:5 (ASV)

And David said to the young man that told him
These tidings:

how know you that Saul and Jonathan his son are dead ?
this he particularly inquired after, as what most affected him, and was most material for him to know; and his meaning is, whether he had this of his own sight and knowledge, or by report.