For our heart shall rejoice in him, because we have trusted in his holy name. (Psalm 33:21)
The root of faith produces the flower of heart-joy. We may not at the first rejoice, but it comes in due time. We trust the Lord when we are sad, and in due season He so answers our confidence that our faith turns to fruition, and we rejoice in the Lord. Doubt breeds distress, but trust means joy in the long run.
The assurance expressed by the psalmist in this verse is really a promise held out in the hands of holy confidence. Oh, for grace to appropriate it. If we do not rejoice at this moment, yet we shall do so, as surely as David’s God is our God.
Let us meditate upon the Lord’s holy name that we may trust Him the better and rejoice the more readily. He is in character holy, just, true, gracious, faithful, and unchanging. Is not such a God to be trusted? He is all wise, almighty, and everywhere present; can we not cheerfully rely upon Him? Yes, we will do so at once and do so without reserve. Jehovah-Jireh will provide; Jehovah-Shalom will send peace; Jehovah-Tsidkenu will justify; Jehovah-Shammah will be forever near; and in Jehovah-Nissi we will conquer every foe. They that know Thy name will trust Thee; and they that trust Thee will rejoice in Thee, O Lord.
C.H. Spurgeon, Faith’s Checkbook