The first Psalm contains a beautiful description of the godly man, namely, the Lord Jesus Christ.
"Blessed is the man that walketh not in the counsel of the ungodly, nor standeth in the way of sinners, nor sitteth in the seat of the scornful. But his delight is in the law of the LORD; and in his law doth he meditate day and night. And he shall be like a tree planted by the rivers of water, that bringeth forth his fruit in his season; his leaf also shall not wither; and whatsoever he doeth shall prosper" (Psalm 1:1-3).
Only the Lord Jesus perfectly fulfilled the characteristics of David's declaration of human godliness. He walked not, stood not, and sat not in fleshly and devilish ways during His earthly life. He loved doing His Father's will, and His heart and mind were passionately devoted to the law of God. He was "the true Vine," and although uprooted by death, He was replanted by resurrection to bring forth the fruit of life to multitudes of others who believe in Him (John 15:1). After making Himself of "no reputation," He now merits all glory (Philippians 2:7-10). And the prosperous success of God's "eternal purpose in Christ Jesus" is assured because our Savior has "overcome the world" (Ephesians 3:11; John 16:33).
The Spirit of this godly Man now lives in all who believe. "God hath sent forth the Spirit of His Son into your hearts" (Galatians 4:6). God undertakes to conform us to the image of the Lord Jesus when we believe (Romans 8:29). While perfect likeness to Christ will not occur during our earthly lifetime, increasingly consistent godliness is to be expected and fulfilled as we "grow in grace, and in the knowledge of our Lord and Savior, Jesus Christ" (I John 1:6; II Peter 3:18). Anything less than this expectation of advancing faith and obedience belies a low view of God, and a weak understanding of the Gospel whereby God works in believers "both to will and to do of His good pleasure" (Philippians 2:13). Provision has been made for sin and failure, and no guarantee of growth into maturity is made (I John 1:9; I Corinthians 3:1). Nevertheless, we should expect and devote ourselves unto the Christlikeness that increasingly results in Psalm 1 describing not only the Lord Jesus, but ourselves as led and enabled by His indwelling Spirit.
The first Psalm first instills in our hearts awe, admiration and adoration for our blessed Lord. Then it beckons us to "walk even as He walked" upon the basis of the wondrous reality that Christ now walks in us (I John 2:6; II Corinthians 6:16). Or, as the Apostle Paul so blessedly assured,
"Beholding as in a glass the glory of the Lord, we are changed into the same image, from glory to glory, even as by the Spirit of the Lord."
(II Corinthians 3:18)