"Though I walk in the midst of trouble, thou wilt revive me: thou shalt stretch forth thine hand against the wrath of mine enemies, and thy right hand shall save me.
The LORD will perfect that which concerneth me: thy mercy, O LORD, endureth for ever: forsake not the works of thine own hands."
Psalm 138:7, 8
Four times, David expresses confidence in God's promises of mercy. He says ...
... God will enliven me.
... God will undertake for me.
... God will save me.
... God will complete me.
The Lord is not indebted to anyone; however, He shows mercy to anyone who places confidence in Him. One amazing attribute of God is His refusal to drop the individual who chooses to make the Lord his strength, even though we all are unworthy of His grace.
Oftentimes, David needed a physical reviving as he faced many foes and ran from numerous enemies who were out for his life. David was well acquainted with exhaustion, fear, and emotional, spiritual, and physical fatigue. As Christians, we too can call on God for strength, both physical strength and spiritual strength; however, in Christ, we have something far better than a promise of God's strength in this life; we have the promise of eternal life, an everlasting "reviving." Jesus said,
"I am the resurrection, and the life: he that believeth in me, though he were dead, yet shall he live:
And whosoever liveth and believeth in me shall never die. Believest thou this?"
John 11:25, 26
David also knew that God would undertake for him against his enemies. God has promised to undertake for anyone who places saving faith in the Son of God.
"What shall we then say to these things? If God be for us, who can be against us?
He that spared not his own Son, but delivered him up for us all, how shall he not with him also freely give us all things?
Who shall lay any thing to the charge of God's elect? It is God that justifieth.
Who is he that condemneth? It is Christ that died, yea rather, that is risen again, who is even at the right hand of God, who also maketh intercession for us."
Romans 8:31-34
David also believed that God would save him. I don't believe that this confidence was limited to physical deliverance. David had made God's righteousness his trust; therefore, he knew that, ultimately, he would be delivered from all enemies, including the greatest enemy of all - death (Psalm 16). We too have such assurance in Christ.
"Wherefore he is able also to save them to the uttermost that come unto God by him, seeing he ever liveth to make intercession for them."
Hebrews 7:25
Lastly, David knew that God would perfect, or complete, him. The Lord had a plan for David's life. God does not step away from His children and leave them to their own devices and the chance of life. God has a plan for our spiritual growth. He plans to bring us to completeness in Christ.
His work of perfecting is ongoing; He is constantly sanctifying us to make us more like His Son.
"Being confident of this very thing, that he which hath begun a good work in you will perform it until the day of Jesus Christ:"
Philippians 1:6
His work of perfection is not only practical but also positional. When I trusted Christ, I was made positionally perfect, or complete, in Him. This is why the Lord performs a daily work of practical sanctification in me.
"For by one offering he hath perfected for ever them that are sanctified."
Hebrews 10:14
David believed that the God Who saved him would also complete him; the Lord would not forsake the very work of His own hands.
Even though David believed that the Lord's mercy would not leave him, he still closes with a humble request for God's abiding presence.
Sometimes, we just need to remind God for our own spiritual benefit. He hasn't forgotten, but we often need to renew our simple dependence upon His mercy by saying,
"Lord, I'm your work in progress. Please, don't leave me. Please, don't forget me."