A godly man, that he may do that which is good and cleave to it, submits to the guidance of the Word of God and makes that familiar to him (verse 2). This is that which keeps him out of the way of the ungodly and fortifies him against their temptations (Psalm 17.4). We need not court the fellowship of sinners, either for pleasure or for improvement, while we have fellowship with the Word of God and with God Himself in and by His Word (Proverbs 6.22). We may judge of our spiritual state by asking, “What is the law of God to us? What account do we make of it? What place has it in us?”
See here: (1) the entire affection which a good man has for the law of God – His delight is in it. He delights in it, though it be a law, a yoke, because it is the law of God, which is holy, just, and good, which he freely consents to and so delights in (Romans 7.16, 22). All who are well-pleased that there is a God must be well-pleased that there is a Bible, a revelation of God, of His will, and of the only way to happiness in Him.
(2) The intimate acquaintance which a good man keeps up with the Word of God – in that law doth he meditate day and night and, by this, it appears that his delight is in it, for what we love, we love to think of (Psalm 119.97). To meditate in God’s Word is to discourse with ourselves concerning the great things contained in it with a close application of mind [and] a fixedness of thought till we be suitably affected with those things and experience a savor and power of them in our hearts. This we must do day and night. We must have a constant, habitual regard to the Word of God as the rule of our actions and the spring of our comforts, and we must have it in our thoughts, accordingly, upon every occasion that occurs, whether night or day. No time is amiss for meditating on the Word of God nor is any time unseasonable for those visits. We must not only set ourselves to meditate on God’s Word morning and evening, at the entrance of the day and of the night, but these thoughts should be interwoven with the business and converse of every day and with the repose and slumbers of every night: When I am awake, I am still with Thee. – Matthew Henry (1662-1714), comment on Psalm 1.2.