seems utterly ignorant

Steven J says...

David, for example, seems utterly ignorant of the principle when he kills many of the surviving descendants of Saul in retaliation for Saul's murder of the Gibeonites),


Actually, Steven, if you read the account a little more clearly, you will see that 'The LORD said, "There is bloodguilt on Saul and on his house, because he put the Gibeonites to death."'

In response to God's instruction, David sought atonement for Saul's sins. He offered to give the Gibeonites just compensation for the evil that Saul had done.

You opt to use the word "retaliation" to identify David's motive; I suspect that for many readers, that word has a familiar connotation which is beyond the author's meaning, which would really be rendered more accurately as "adequate compensation" or "atonement".

The account tells us that David was seeking a blessing on Israel; it doesn't tell us that David was satisfying some sort of bloodlust rage.

We also note that it was not David that killed Saul's descendants. Rather, it was the Gibeonites who put the men to death. David equitably satisfied the compensation requested by the Gibeonites.

You likely consider this a minor point, that David handed over the men to the Gibeonites to be put to death, rather than killing the men himself. You are likely to see this as a trivial distinction unworthy of note.

But I suggest to you that the author of the account does deem this particular point to be "worth noting". It's of sufficient importance to be noted by the author.

You also suggest that David is "utterly ignorant" of the LORD's principles. Yet in the account we read that it is the LORD himself that gives David instruction, pointing out that there has been no atonement made for Saul's sin.