A confrontation between a hunted man and his pursuer reaches its most powerful moment when the victim steps back and hands the ultimate decision over to heaven. Rather than seeking justice through human courts, David places the entire conflict between himself and Saul directly into the hands of God. He lays out a complete, multi-stage legal system where God fills every single role in the courtroom.
Initially, God serves as the presiding judge who receives and listens carefully to the claims of both sides [מלבי״ם]. At the same time, He acts as the sole witness who sees every hidden detail of the events that have transpired [אלשיך]. As the trial progresses, God steps into the role of the advocate, actively arguing David's case and managing his legal battle [מלבי״ם, מצודת ציון]. Finally, the process reaches the moment of decision and execution. God delivers the final verdict based on absolute truth, and then acts as the executor of that justice by physically rescuing David from Saul's grasp [מלבי״ם, אלשיך].
A subtle but profound message is woven into the specific way David refers to God during this plea. He deliberately uses the Divine Name associated with mercy rather than the one associated with strict justice. This serves as a sharp warning to Saul. It suggests that Saul's actions are so severe that even if his case is evaluated through the lenient lens of mercy, he will still be found entirely guilty [אלשיך].
These piercing words have an immediate and profound impact. The moment David finishes speaking, Saul is broken. Recognizing David's complete innocence, he bursts into tears and tenderly calls him his son. This affectionate address stems both from the fact that David is his son-in-law, married to his daughter Michal, and from the deep realization that David just treated him with the gentle mercy a loving son shows a father. In a moment of total clarity, Saul confesses the painful truth: while he had relentlessly pursued David with evil intentions, David had only repaid him with pure goodness, choosing to spare his life when he had every opportunity to take it [אברבנאל].