There are two truths that seem obvious from this reading.
We need wholehearted commitment to God’s word. This is stated right at the start. With my whole heart I cry; answer me, O Lord! I will keep your statutes (145). The author’s main request is that he be saved that he might keep the word. He says, save me, that I may observe your testimonies (146). The desire to rise early to meditate on the word also indicates a strong commitment. My eyes are awake before the watches of the night, that I may meditate on your promise (148).
The persistence to continue in the word even when things are not going well shows the wholeheartedness of the commitment. Look on my affliction and deliver me, for I do not forget your law (153). Many are my persecutors and my adversaries, but I do not swerve from your testimonies (157).
We need wholehearted commitment to the whole of God’s word. It is not just a word of God that is the truth but “the sum of that word” that is truth (160). All of it together makes it true and enduring. A picked over, condensed version of God’s will is not God’s will but the will of the one who did the condensing. The New Testament says the same thing in several places (2 Tim 3:16-17; Matt 5:19; James 2:10)
We will never find that the scriptures equip us for every good work until we wholeheartedly commit ourselves to the whole of God’s word. Is there some part we have never read? We better read it. Is there some part we have neglected to apply in our lives? We must draw out its examples and apply them in our lives. Is there some command we have not obeyed? We must obey it.