Living under the constant threat of hostile pursuers takes a severe toll on a person's mind and speech. The primary approach among commentators is that relentless pressure from enemies causes such profound sorrow and worry that all the speaker's words are reduced to expressions of sadness and crying [רש״י, מצודת דוד, ביאור שטיינזלץ]. This grief is sometimes inflicted specifically because of the speaker's steadfast trust in God [אבן עזרא]. Conversely, the enemies' actions might not bring sorrow, but rather intense frustration, provoking angry outbursts [מאירי]. This is especially true when the enemies challenge matters concerning his royal authority [רד״ק]. Another perspective suggests a more direct conflict, where the enemies simply contradict and constantly defy whatever he says [ביאור שטיינזלץ].
This struggle over speech is deeply connected to the time David feigned madness before Achish, the Philistine king. In this vulnerable state, David experiences deep distress over the misuse of his voice. Instead of spending his time speaking words of Torah and praising God to secure His protection, David is forced to spout nonsense and act like a fool [אלשיך].
His Philistine enemies, however, refuse to believe the act. They make his strange speech the central focus of their attention [ביאור שטיינזלץ] and actively try to turn the king against him, claiming David is actually a spy sent to scout their land [מלבי״ם]. Because the Philistines suspect his madness is merely a cover for a plot to harm them, David is forced to maintain his foolish facade continuously throughout the entire day, rather than just during his moments in the royal court [אלשיך]. Ultimately, even after the king dismisses David without punishment, the danger does not pass. His enemies remain fixated on him, continuously harboring malicious thoughts and plotting his downfall [מלבי״ם].