| Barnes' Notes on the Bible I rejoice at thy word, as one that findeth great spoil - Plunder in a camp; prey; booty: as the hunter or the warrior, when he lights on great and unexpected success.
Clarke's Commentary on the BibleAs one that findeth great spoil - שלל רב shalal rab. This appears to refer to such spoil as is acquired by stripping the dead in a field of battle, taking the rich garments of the slain chiefs; or it may refer to plunder in general. As God opened his eyes he beheld wonders in his law; and each discovery of this kind was like finding a prize.
Gill's Exposition of the Entire BibleI rejoice at thy word, as one that findeth great spoil. At having it, which is a distinguishing blessing; all are not favoured with it; and is an inestimable treasure, a field in which a treasure lies; which those that find rejoice at, and especially at the understanding of it, as Kimchi notes: for such only delight in it who spiritually understand it, or have an application of it to them; find it, and eat it, and then it is the joy and rejoicing of their hearts. The doctrines of it are matter of great joy, particularly which concern the grace of God, the person of Christ, and peace, pardon, righteousness, and salvation by him; and each of its promises, which are exceeding great and precious; and, when opened and applied in a time of need, occasion great joy; such as is expressed at finding a great spoil, when much substance comes into the hands of the conqueror, as well as victory. The word is a part of the believer's spiritual armour, by which he overcomes his enemies; as well as it acquaints him with the conquest Christ has obtained over them, and made him a sharer in; and directs him to unsearchable riches, to things more valuable than thousands of gold and silver; so that he has great reason to rejoice at it in such a manner indeed! see Isaiah 9:2.
Geneva Study BibleI rejoice at thy word, as one that findeth great spoil.
Jamieson-Fausset-Brown Bible Commentary162. (Compare Mt 13:44, 45). Though persecuted by the mighty, the pious are not turned from revering God's authority to seek their favor, but rejoice in the possession of this "pearl of great price," as great victors in spoils. Hating falsehood and loving truth, often, every day, praising God for it, they find peace and freedom from temptation.
Matthew Henry's Concise Commentary119:161-168 Those whose hearts stand in awe of God's word, will rather endure the wrath of man, than break the law of God. By the word of God we are unspeakable gainers. Every man hates to have a lie told him, but we should more hate telling a lie; by the latter we give an affront to God. The more we see the beauty of truth, the more we shall see the hateful deformity of a lie. We are to praise God even for afflictions; through grace we get good from them. Those that love the world have great vexation, for it does not answer what they expect; those that love God's word have great peace, for it outdoes what they expect. Those in whom this holy love reigns, will not perplex themselves with needless scruples, or take offence at their brethren. A good hope of salvation will engage the heart in doing the commandments. And our love to the word of God must subdue our lusts, and root out carnal affections: we must make heart work of it, or we make nothing of it. We must keep the commandments of God by obedience to them, and his promises by reliance on them. God's eye is on us at all times; this should make us very careful to keep his commandments.
Matthew Henry's Whole Bible CommentaryVerse 162 Here is, 1. The pleasure David took in the word of God. He rejoiced at it, rejoiced that God had made such a discovery of his mind, that Israel was blessed with that light when other nations sat in darkness, that he was himself let into the understanding of it and had had experience of the power of it. He took a pleasure in reading it, hearing it, and meditating on it, and every thing he met with in it was agreeable to him. He had just now said that his heart stood in awe of his word, and yet here he declares that he rejoiced in it. The more reverence we have for the word of God the more joy we shall find in it. 2. The degree of that pleasure-as one that finds great spoil. This supposes a victory over the enemy. It is through much opposition that a soul comes to this, to rejoice in God's word. But, besides the pleasure and honour of a conquest, there is great advantage gained by the plunder of the field, which adds much to the joy. By the word of God we become more than conquerors, that is, unspeakable gainers. | 
