Not surprisingly, as Luther does time and time again, he also focuses on God's Word and its importance, power, and central role in growing fruit and pleasing our God.
Psalm 1 is a psalm of comfort. It admonishes us to gladly hear and learn God's Word and brings us the comfort that, in so doing, we will have many and great benefits. Just as a palm tree by the water grows green and brings fruit despite all heat and cold and the like, so also all our words and works will prosper despite all enemies. Human doctrines do not have this benefit, and, as the wind blows the chaff away, so they also pass away. For God says that those who study His word please Him, but the others He allows to perish.
This psalm flows from the Third Commandment; indeed, it is part of that commandment, for the command to honor the Sabbath is itself the command to hear and learn of God's Word. Psalm 1 is also included in the Second and Third Petitions of the Lord's Prayer, for in these we pray for God's kingdom and His will, both of which are conveyed by His Word. (Reading the Psalms with Luther)
Quoting Psalm 1:
Blessed is the man who walks not in the counsel of the wicked, nor stands in the way of sinners, nor sits in the seat of scoffers;
But his delight is in the law of the Lord, and on his law he meditates day and night. He is like a tree planted by streams of water that yields its fruit in its season, and its leaf does not wither. In all that he does, he prospers.
The wicked are not so, but are like chaff that the wind drives away.
Therefore the wicked will not stand in the judgment, nor sinners in the congregation of the righteous; for The Lord knows the way of the righteous, but the way of the wicked will perish.
O God, thanks and praise belong to You because You have given us Your Holy Word. Enlighten us by Your Holy Spirit to understand Your counsel of grace in Jesus Christ, to love Your Word, and to take delight in learning Your statutes and walking in Your Law. Bestow Your blessing and prosperity on the works of our hands in our Christian calling and all our conversation. Amen.(Reading the Psalms with Luther)