Let my soul live . . .
It is only by the power of God that we live and move and have our being (Acts 17:28). John tells us in John 1:9 That was the true Light, which lighteth every man that cometh into the world. We owe our whole life to Jesus Christ, for He is the Great Creator of everything. As long as we live, then, we shall give our souls to him in faith and our bodies a living sacrifice (Romans 12:1-2).
. . . and it shall praise thee
That is, our soul shall praise God. Psalm 3:2 Many there be which say of my soul, There is no help for him in God. Selah. These are the many who do not see the reality of God's Providence and His care over His creatures. The hairs of our head are numbered (Matthew 10:30), and no sparrow falls to the ground without his knowledge and care (Matthew 10:29).
Since this is so, we should praise our God, who gives us life and strength and sustenance every day of our lives. Praising Him is being joyful in the heart for his benefits and singing, praying, speaking, and writing of Him. We also praise Him in our church attendance, which the Scriptures tell us not to forsake (Hebrews 10:25) and giving of our substance to support the Kingdom of God and His churches.
. . . and let thy judgments help me.
God's judgments refer to His word, the Bible. These are the judgments which each one of us needs to heed. Therefore, we must read it much, learn it, memorize it, write it, and practice it. If we are alive and are praising God, then we will love his commandments, which are not grievous (I John 5:3). Enjoy this day by praising God and allowing his judgments to help you.