Psalm 27:1-4 (ESV)
The Lord is my light and my salvation;
whom shall I fear?
The Lord is the stronghold of my life;
of whom shall I be afraid?
 When evildoers assail me
to eat up my flesh,
my adversaries and foes,
it is they who stumble and fall.
 Though an army encamp against me,
my heart shall not fear;
though war arise against me,
yet I will be confident.
 One thing have I asked of the Lord,
that will I seek after:
that I may dwell in the house of the Lord
all the days of my life,
to gaze upon the beauty of the Lord
and to inquire in his temple.
The church of Jesus Christ shall conquer. That is a simple Christian axiom which is true and which will prove itself out over time and is not being denied in any measure anywhere in the world today by the troubles that plague it.
Psalm 27 is a war Psalm. David claims that he shall not be afraid of his enemies because God is on his side. The enemy may surround him (verse 3 ), assail him (verse 2), and war against him (verse 3), he will not fear. The full application of this is not warfare, at least not warfare in the sense we normally think of it. This Psalm is for the church of Jesus Christ in its battles against principalities and powers in heavenly places (Ephesians 6:10-19).
The warfare we are in is more serious, more deadly and its consequences more dismal and exhilarating than mere physical warfare. Our goal is the house of the lord (Verse 4) and the enemy’s plan is to ensure that we do not achieve it. We are in a war for our souls (I Peter 2:1). Our weapons are not the weaponry of warfare (II Corinthians 10:3-4). Our enemies are not human beings or countries or armies (Ephesians 6:10-13). Our tactics are not the well learned lessons of thousands of years of battle (II Corinthians 10:5). Our protection is not armour or embattlements (Psalm 119:114; Ephesians 6:16).This war is real and it is fierce and it has severe casualties. And for all those who are truly His the outcome is guaranteed victory.
Every battle verse in Psalm 27 relates to the spiritual warfare we are in against the enemy of our souls. We do not need to fear him (verse 1, 3), for God has already defeated him and we are safe. He stumbles when we resist (verse 2 and James 4:7). We can be confident in this war for the outcome is certain (verse 3). We must never lose sight of the goal in this war (verse 4). God is our protector (verse 5). The devil may be the prince of the power of the air but we shall turn his territory into a place of worship (verse 6).
There is another legitimate way in which to take these verses. It is true that they speak of our spiritual warfare against the evil one. But they also tell us about Jesus who has defeated him. He has no fear of Satan. He has already dealt him the death blow. He has no fear at all. When He was here winning the war for us He looked ahead to the reward awaiting Him and was able to finish His work (Verse 4 and Hebrews 12:1-2). He is now enthroned as the reigning king of all things (Verse 6).
What a glory it is to be a child of God, or, in the metaphor of this Psalm, a soldier of the King. We follow the Captain who has already guaranteed the victory, who still fights for us, who works out everything out after the counsel of His own will and for our good. There is simply no better place to be than in this army of rescued soldiers.