In Psalm 103:1, David says, "Bless the LORD, O my soul: and all that is within me, bless his holy name. " David was literally commanding his mind, his will, his emotions, his whole being, to unify, join together as one and bless the Lord. Not once, but he called on his soul to bless the Lord, repeatedly. Why?
Verse 2 speaks of how God has provided and made available certain benefits to man, and verses 3-17 outlines these benefits. They speak of God's forgiveness, healing, redemption, protection and deliverance, His boundless love and mercy toward those that fear Him and His unending righteousness to their children's children.
So David commands his soul, his whole inner being to give the Lord his best worship and highest praise for all God has done, and will continue to do for those who fear and reverence Him.
Therefore, I will remind my soul to bless the Lord, and to give Him the highest praise for all He's done, all He has provided, and all of His tender mercies and compassion that He continues to extend to me and my loved ones. And in utter gratefulness, I will command my soul to bless the Lord for His infinite mercies and unending love He continues to lavish upon me daily.
Soul, bless the Lord and all that is within me. Bless His holy name!