We have seen David defend his sheep from a lion.  Now the king of Israel is in bad spirits and his advisors need a way to calm his madness.  Someone is aware of David’s music and songs.  They suggest that David is more than a little boy with a harp.  He must have been a bit of a warrior to dispatch the lion.  This is not a self absorbed modern musician with legions of admiring fan girls.  The Psalms of faith are actually a source of spiritual warfare which David has mastered.

Then answered one of the servants, and said, Behold, I have seen a son of Jesse the Bethlehemite, that is cunning in playing, and a mighty valiant man, and a man of war, and prudent in matters, and a comely person, and the LORD is with him.  1 Samuel 16: 18

Spiritual music is powerful in expressing faith in God against the threats David would face.  As he entered the court of Saul he was standing in the presence of the first of many human enemies.  These would become a common theme of David’s prayer for deliverance.

O LORD my God, in thee do I put my trust: save me from all them that persecute me, and deliver me:  Lest he tear my soul like a lion, rending it in pieces, while there is none to deliver.  O LORD my God, If I have done this; if there be iniquity in my hands;  If I have rewarded evil unto him that was at peace with me; (yea, I have delivered him that without cause is mine enemy:)  Let the enemy persecute my soul, and take it; yea, let him tread down my life upon the earth, and lay mine honour in the dust. Selah.  Arise, O LORD, in thine anger, lift up thyself because of the rage of mine enemies: and awake for me to the judgment that thou hast commanded.  So shall the congregation of the people compass thee about: for their sakes therefore return thou on high.  Psalm 7: 1-7

David checks his own walk before asking deliverance.  As a warrior checks his weapons before battle, we have to be sure we are not letting darts pass through flaws in our armor.  The spiritual song of our warfare is empowered by righteousness.  This is the kind of spiritual weapons training that David brought to Saul’s court;

The LORD shall judge the people: judge me, O LORD, according to my righteousness, and according to mine integrity that is in me.  Oh let the wickedness of the wicked come to an end; but establish the just: for the righteous God trieth the hearts and reins.  My defence is of God, which saveth the upright in heart.  God judgeth the righteous, and God is angry with the wicked every day.  If he turn not, he will whet his sword; he hath bent his bow, and made it ready.  He hath also prepared for him the instruments of death; he ordaineth his arrows against the persecutors.  Behold, he travaileth with iniquity, and hath conceived mischief, and brought forth falsehood.  He made a pit, and digged it, and is fallen into the ditch which he made.  His mischief shall return upon his own head, and his violent dealing shall come down upon his own pate.  I will praise the LORD according to his righteousness: and will sing praise to the name of the LORD most high.  Psalm 7: 8-17

David sings about righteousness as if God is his protection.  Lies and deception are portrayed in their vulnerability to the wrath of God.  David uses song and praise as his warfare.

For he put on righteousness as a breastplate, and an helmet of salvation upon his head; and he put on the garments of vengeance for clothing, and was clad with zeal as a cloak.  Isaiah 59:17

The songs of David develop into a relationship that hints at revelation God shares with David.  He has recognized that God has created man lower than angels but destined to something greater.  David will be aware of the coming Messiah and will deliver prophesy of him in his psalms.

O LORD, our Lord, how excellent is thy name in all the earth! who hast set thy glory above the heavens.  Out of the mouth of babes and sucklings hast thou ordained strength because of thine enemies, that thou mightest still the enemy and the avenger.  When I consider thy heavens, the work of thy fingers, the moon and the stars, which thou hast ordained;  What is man, that thou art mindful of him? and the son of man, that thou visitest him?  For thou hast made him a little lower than the angels, and hast crowned him with glory and honour.  Thou madest him to have dominion over the works of thy hands; thou hast put all things under his feet:  All sheep and oxen, yea, and the beasts of the field;  The fowl of the air, and the fish of the sea, and whatsoever passeth through the paths of the seas.  O LORD our Lord, how excellent is thy name in all the earth!  Psalm 8: 1-9

This relationship of praise is like the military artillery observers in modern warfare.  They take small teams to places where they can report enemy movement to the artillery.  The power of God is called by the prayers of our observed needs.  Praise and worship in song is part of that communication, our communion.

I will praise thee, O LORD, with my whole heart; I will shew forth all thy marvellous works.  I will be glad and rejoice in thee: I will sing praise to thy name, O thou most High.  When mine enemies are turned back, they shall fall and perish at thy presence.  For thou hast maintained my right and my cause; thou satest in the throne judging right.  Thou hast rebuked the heathen, thou hast destroyed the wicked, thou hast put out their name for ever and ever.  O thou enemy, destructions are come to a perpetual end: and thou hast destroyed cities; their memorial is perished with them.  But the LORD shall endure for ever: he hath prepared his throne for judgment.  And he shall judge the world in righteousness, he shall minister judgment to the people in uprightness.  The LORD also will be a refuge for the oppressed, a refuge in times of trouble.  And they that know thy name will put their trust in thee: for thou, LORD, hast not forsaken them that seek thee.  Psalm 9: 1-10

Praise, rejoice, and sing.  Confidence in our redeemer brings joy, and we make a sacrifice of praise to confirm that confidence.  We pray against spiritual powers and principalities in the same way David prayed against his human enemies.  We witness the same destruction of enemies and the same deliverance from God as we praise him today.  David was not just some sweet little boy singer, but rather the demonstration of spiritual warfare.  He could stand in the presence of his enemies with confidence.  He was a man of war.