Gemma Animae reads three Old Testament battles through the same allegorical lens, with Christ as the hero in each case.
David and Christ, Goliath and the Devil compared
When Jesus, or Joshua, for they are the same, had defeated many foes and the victorious people became lax in the long peace that followed, the Philistines once again rose against Israel and waged a bloody war on them. Goliath steps out from their lines and asks for a duel. David comes against him with his shepherd’s bag and sling. Having knocked him down, he kills him with his sword. The liberated people sacrifice a victim to God and jubilate their praise and thanksgiving, then meet David on his way to Jerusalem and receive their savior with hymns.
In the same way, when the Christian people have overcome the vices once they rise once again and bring another bitter war to the negligent soul. The devil, our Goliath, comes forth and asks for a duel when he tempts Christians to each of the vices. Strengthened by Sacred Scripture, the soul comes against him with its milk bucket  and slings a stone when it defeats him through the humanity of Christ (which was a stone to the thirsting people  and the corner-stone to those who believe in him). Having laid the devil low, the soul beheads him with his own sword when it overcomes the malignant foe through fragile flesh.
 The Biblical account doesn’t mention a milk bucket. I Kings 17:38-40:
Saul clothed David with his armor; he put a bronze helmet on his head and clothed him with a coat of mail. David strapped Saul’s sword over the armor, and he tried in vain to walk, for he was not used to them. Then David said to Saul, “I cannot walk with these; for I am not used to them.” So David removed them. Then he took his staff in his hand, and chose five smooth stones from the wadi, and put them in his shepherd’s bag, in the pouch; his sling was in his hand, and he drew near to the Philistine.
 An allusion to the Paul’s interpretation of Exodus 17, where Moses draws water from the rock for the thirsty Israelites. 1 Cor. 10:4 “For they drank from the spiritual rock that followed them, and the rock was Christ.”
CAP. LXXVIII. – De David cum Christo et Goliath cum diabolo comparatis.
Multiplici itaque hoste, ab Iesu, qui et Iosue, superato, et victori populo ob pacis abundantiam negligentia resoluto, rursus Philistaei adversus Israel conveniunt, crudele bellum indicitur. Ex quibus Goliath procedit, duellum petit. Cui David cum pastorali pera occurrit funda, et lapide cum deiecit, proprio mucrone perfodit. Populus autem liberatus, pro victoria Deo immolat victimam, pro gratiarum actione laudes iubilat. David Hierusalem venienti turba populorum obviam ruit, salvatorem populi hymnis excepit. Sic quoque vitiis a Christiano populo superatis, denuo consurgit, negligenti animae acrius bellum infertur. Ex quibus gigas Goliath, scilicet diabolus, procedit, duellum petit, dum quemlibet Christianum ad singularia vitia allicit. Cui fortis animus cum sacra Scriptura, ut David, cum mulcro lactis occurrit funda, et lapide, deiecit: dum per humanitatem Christi quae sitienti populo erat petra, et credentibus populis lapis angularis eum devincit, proprio ense prostratum iugulat, dum hostem malignum fragili carne superat.
Thus when the subdeacon and other ministers commence the sacrifice, it is like David is being armed by Saul and the people (1 Kings 17). When the oblations are placed on the altar, David’s weapons are laid there. Then when the pontiff comes to the altar, David moves against the Philistines. The chalice is his milk bucket, the corporal his sling, the oblation his rock. The sung Preface is the cheering of Goliath’s comrades egging the giant on to fight. The Canon is the people’s prayer. The priest’s bow is the stone’s swinging in the sling. The elevation of the bread is the casting of the stone. When he bows again, he signifies that the enemy has been knocked down. When the deacon comes to the priest, elevates and puts down the chalice, he indicates that David has run to the prostrate giant and taken off his head with his drawn sword. Finally, after giving the peace the people communicates because having received peace through David they participate in God through sacrifice. The Communion chant is the people’s praise, flush with victory. The [Postcommunion] prayer and [final] blessing that follow is the trophy the people of Jerusalem gave David upon his return. At the end of all these things, the people go back to their homes, because after their victory the people returned home with joy.
CAP. LXXIX. – Mysterium
Cum ergo a subdiacono, et aliis sacrificium instituitur, quasi David a Saul et populo armis induitur (I Reg. XVII). Cum oblationes super altare ponuntur, quasi arma David deponuntur. Porro cum pontifex ad altare venit, quasi David adversus Philistaeum procedit. Per calicem mulctrale accipitur, per corporale funda, per oblatam petra intelligitur. Praefatio quae cantatur, fuit clamor quo pugil gigas ad duellum provocabatur, per Canonis deprecationem, intelligimus populi orationem. Sacerdotis inclinatio, est fundae lapide imposito rotatio. Panis elevatio est lapidis iactatio. Ubi denuo inclinatur, significat quod hostis prosternitur. Ubi autem diaconus ad sacerdotem venit, et calicem cum eo elevans deponit, designat quod David ad prostratum cucurrit, extracto gladio caput abstulit. Deinde data pace populus communicat quia accepta per David pace populus Deo sacrificans participat. Cantus in communione, est laus populi pro victoriae exsultatione. Oratio et benedictio quae sequitur, est trophaeum quo David a populo Ierusalem veniens excipiebatur. His peractis, populus ad propria remeat, quia populus tunc post victoriam cum gaudio ad propria repedabat.