The murder of the כהנים of Nob had repercussions down through Jewish history. Some four months after this incident, Saul will be facing his final battle against the Philistines:
So Saul’s death comes in part as a result of Nob.
But it goes much further. There’s an incident at the end of שמואל ב that we will have to deal with in detail when we come to it, but at the simplest level it is horrifying:
Who were the גבענים and when did Saul kill them בקנאתו לבני ישראל ויהודה? They were the non-Jewish nation that served in the משכן:
The Yerushalmi explains that they were the remnant of Nob. The כהנים were not seeking revenge, but the גבענים were affected by the atrocity as well:
So the last of Saul’s lineage is wiped out because of Nob. The נביא only mentions this indirectly, but I think that is because of the nature of ספר שמואל: it was written by Samuel and his school. Samuel was the prophet of the destruction of the משכן and of the line of עלי: (שמואל א ב:לא) הנה ימים באים וגדעתי את זרעך ואת זרע בית אביך מהיות זקן בביתך. I think, while the crime was not minimized, there is a sense that it was inevitable.
David takes responsibility for what happened at Nob. חז״ל see the repercussions of David’s actions later in his life, and even in future generations:
First, where does the idea that ה׳ gave David a choice of punishments come from? G-d doesn’t ask man what the appropriate מגה כנגד מדה is! David is different; as the embodiment of מלכות, he represents ה׳'s rulership in the world and he does get to decide how that world is run:
So once he has backed down and doesn’t want to die in the hands of his enemies, he is left with the realization that his descendents will be killed: