Fleeing for his life, an unarmed David arrives at the Tabernacle in Nob. As a sanctuary of holiness and peace, the Tabernacle is naturally devoid of weapons, yet it houses one artifact of immense historical significance: the sword of the fallen Philistine giant, Goliath. The priest offers this unique weapon to David, noting that it is kept wrapped and covered in a cloth [רש״י, מצודת ציון, רד״ק].
The sword is stored within the priests' chambers, concealed behind the Ephod. The primary approach among commentators understands this placement physically; the sword rested behind the priestly garments, including the Ephod and breastplate [מצודת דוד, מצודת ציון, רלב״ג, רד״ק]. It was kept there as a lasting memorial to publicize the great miracle of the Israelites' victory for all future generations [רלב״ג, רד״ק, ביאור שטיינזלץ]. Alternatively, this detail describes a sequence of events rather than a physical location, suggesting the priest only offered the sword after David had sought guidance from God using the Urim and Thummim contained within the Ephod [רש״י, מצודת דוד, רד״ק].
On a deeper, symbolic level, the specific manner in which the sword was stored served as a reminder of the controversy surrounding David's ancestry following his victory over Goliath. The cloth wrapping the sword hints at the garment of Ruth the Moabite, the matriarch of David's royal line. Its placement behind the Ephod alludes to Samuel the Prophet, who wore a linen ephod and decisively ruled that David was legally fit to enter God's congregation and assume the kingship [אלשיך].
The priest presents the sword by explaining that it is the only weapon available in the sanctuary [מצודת ציון]. He is somewhat reluctant to remove a sacred memorial from its resting place. However, because there are no other arms available, and because David himself struck down the Philistine and originally brought the sword to the Tabernacle, he has the absolute right to reclaim it [רד״ק]. In offering it, the priest also questions whether David intends to use the weapon himself or give it to one of his attendants [אלשיך].
David's response reveals his profound appreciation for the weapon. Although Goliath's sword was massive, heavy, and not particularly practical for combat, David considers it superior to any other blade [מצודת דוד, ביאור שטיינזלץ]. Typically, soldiers avoid wielding the weapon of a fallen enemy, fearing it carries a bad omen. David, however, views the sword in the exact opposite light. To him, it is a tangible symbol of the miracle he experienced and a clear sign that God is with him and will deliver him from his enemies [מלבי״ם, חומת אנך]. Recognizing its deep personal and spiritual value, David demands the sword for himself, knowing it belongs in his hands more than anyone else's [אלשיך].