Psalm 9

Read Psalm 9 ESV

Who - David writes this psalm as a song to be song in a public setting.  If not or originally written for a choir at the temple, then it was adopted for such.

What - It is a song that recounts God's deeds for David and by extension for Israel.  It ends with a request for God to judge the nations and put the fear of God in them (vs 20).  As David recounts the deeds of the LORD, he is focusing on God's actions for David against his enemies and the nations who have come against him. So this song appears to be a request for God to act against the idolatrous nations who are against Israel.

When - Unstated

Where - Most likely Jerusalem

Why - From the way this psalm progresses and the request David makes to the LORD it appears David, and all who sing/recite this psalm, is asking God to act on their behalf against the peoples/nations who are against them.  However, these nations have no fear of God or worship of Yahweh.

How - David starts with praise to God recalling his wondrous deeds and when David’s enemies stumble, turn back and perish before he LORD.  David then states his reason (vs4) because he LORD has maintained David’s just cause and given righteous judgment on David’s behalf.  he LORD judges from His throne.  David declares he LORD is a stronghold and refuge for the oppressed and those who trust in Him.  David calls to he LORD asking for Him to see his affliction and act for David so he may praise God before the people.  Then David ask he LORD to act for them against these nations again and deliver Israel from their attacks.

So What 

1. Here is a model for approaching God anytime we need deliverance.  We can recount the promises of God as reasons for His acting as well as the praise to Him deliverance will bring about.  The end goal of God acting is so he will be praised.  
2. When we are delivered we should sing and worship the LORD as part of our thankfulness.
3. While seeking deliverance from a foe, our desire should be that our enemy becomes a disciple of Christ.  This psalm is rightly applied when in conflict or oppressed by ungodly wicked persons.  It is inappropriate to apply this psalm to another Christian we are in conflict with.
4. We have to recognize that no matter what actions he LORD takes in this life on earth, the praise for deliverance is not fully realized until we delivered into eternity through faith in Christ.