Psalm 18 is one of my favorite texts in the Bible. In it we find the Lord working mightily for his people:

Psalm 18:6-19

6 In my distress I called upon the Lord;
to my God I cried for help.
From his temple he heard my voice,
and my cry to him reached his ears.

7 Then the earth reeled and rocked;
the foundations also of the mountains trembled
and quaked, because he was angry.
8 Smoke went up from his nostrils,
and devouring fire from his mouth;
glowing coals flamed forth from him.
9 He bowed the heavens and came down;
thick darkness was under his feet.
10 He rode on a cherub and flew;
he came swiftly on the wings of the wind.
11 He made darkness his covering, his canopy around him,
thick clouds dark with water.
12 Out of the brightness before him
hailstones and coals of fire broke through his clouds.

13 The Lord also thundered in the heavens,
and the Most High uttered his voice,
hailstones and coals of fire.
14 And he sent out his arrows and scattered them;
he flashed forth lightnings and routed them.
15 Then the channels of the sea were seen,
and the foundations of the world were laid bare
at your rebuke, O Lord,
at the blast of the breath of your nostrils.

16 He sent from on high, he took me;
he drew me out of many waters.
17 He rescued me from my strong enemy
and from those who hated me,
for they were too mighty for me.
18 They confronted me in the day of my calamity,
but the Lord was my support.
19 He brought me out into a broad place;
he rescued me, because he delighted in me. (ESV)

What an image of God rousing himself to rescue his people, with the whole of Heaven trembling from the force of his might! What enemy can stand before the Lord our God?

But the Psalmist, David, makes an unusual claim:

Psalm 18:20-24

20 The Lord dealt with me according to my righteousness;
according to the cleanness of my hands he rewarded me.
21 For I have kept the ways of the Lord,
and have not wickedly departed from my God.
22 For all his rules were before me,
and his statutes I did not put away from me.
23 I was blameless before him,
and I kept myself from my guilt.
24 So the Lord has rewarded me according to my righteousness,
according to the cleanness of my hands in his sight. (ESV)

How does this line up with what we find elsewhere that no one is righteous, that no one is blameless before the Lord? How can David claim that God acts because David is righteous? Are we finding here evidence that people are capable of living righteously before God and that God will reward them for that righteousness?

It looks that way – until we keep reading.

Psalm 18:31-33

31 For who is God, but the Lord?
And who is a rock, except our God?—
32 the God who equipped me with strength
and made my way blameless.
33 He made my feet like the feet of a deer
and set me secure on the heights. (ESV)

God responding to the righteousness in David is God responding to the righteousness he put in David. David did not make his way blameless, God made his way blameless. Anything in David that is praiseworthy, anything that might draw the eye of God, is only there because God has given it. God made his way blameless and made his feet secure.