In this fifth section of the psalm, the author asks for personal Bible instruction: ‘Teach me, O Lord, the way of your statutes.’ The psalmist knows that such divine teaching involves more than mere knowledge. In addition the Teacher enables the student to practise what he is taught. Therefore the psalmist can say with confidence: ‘I will keep it to the end.’ This is not presumption. If he had said anything else, it would be an expression of unbelief.
In verse 34, the psalmist admits his need of understanding. If he does not know why he is doing God’s law, then his obedience would only be external. True obedience involves inner commitment of both mind and affections. The best way for this to happen is for the Lord to be present, leading his pupil in the right way (v. 35). As Spurgeon said, ‘This is the cry of a child that longs to walk, but is too feeble; of a pilgrim who is exhausted, yet pants to be on the march; of a lame man who pines to be able to run.’ God’s instructions are given to such intimately and not from a distance. This understanding is the benefit he gives to those who delight in his law.
The big danger to such devotion is selfish gain (v. 36). Such things in reality are worthless (v. 37), although we need divine illumination to realise it. The psalmist knows the danger of attempting to go in God’s ways without having spiritual life. Therefore he speaks to God about his concern because he knows that the Lord has promised to give spiritual help to his people (v. 38).
For some reason, the psalmist fears reproach (v. 39). He does not specify what the reproach is – it could be that a failure by him to obey God would cause his opponents to deride him, or it could be that he was apprehensive of persecution from those who would be against his commitment to God’s will. Yet God’s laws remain good whatever happens to the psalmist – that is, good in essence and good to experience.
Since that is the case, the psalmist longs to obey God (v. 40). It would be unjust of the Lord to deny more life to one who wants to obey him. ‘Here past fruits of grace are made the plea for further blessing’ (Spurgeon). The psalmist is asking the One who began the good work in him to continue it. That is the best way to respond to the Teacher.