Psalm 144 Part 1.

This psalm is believed to have been written near the time David came to be recognized as the king over all the tribes of Israel, and the psalm expresses David’s heart for the nation in both war and peace. From vs 2 & 10, we assume that it was written after his ascension to the throne, with v5 telling us that he still had enemies to conquer, e.g.the Philistines. The psalm itself is a bit of a scrapbook of compiled verses cut and pasted from other psalms. But even scrape books are put together for a reason, and in this compilation, you will see 9 pictures of God in the opening 2 verses. (Notice the personal pronouns in this passage.) Turn the pages and there you see pictures of yourself (v3ff) Then come the action pages! 
In applying v1 personally, God is training us to use spiritual weapons – such as the sword of the Spirit, which is the word of God (c.f. Eph.6:10-12) – then training must always continue. It is never ‘who trained my hands for war,’ but always in the present: ‘who trains my hands for war.’

As he began, David poured out 9 attributes, names and titles for God, each representing some aspect of God’s character, or help that had been of use in battle. David knew God’s help and presence in many ways, not just one or two. Note that David began with ‘my lovingkindness.’ He loved and valued God for being his rock, his fortress, his mentor for battle, his high tower, his deliverer, his shield, his refuge, and his conquering victory. Yet first among all those was the gift from God of lovingkindness, and faithfulness!

In the opening lines, David exalted God’s great strength and victory. In light of that, it amazed David that God would have an interest in him, or in humanity in general. Ps.8:4 is the same questions as vs3-4 but from a slightly different perspective. Here the emphasis is on the LORD as a warrior that none can oppose. In Ps8:4 the emphasis is on the power of God as Creator and sustainer of the universe.