40:11-12 The upbeat spirit of this psalm changes dramatically at verse 11. David appealed to the Lord for continuing deliverance on the basis of God's past salvation and the psalmist's personal dedication to God. He referred to his troubles as rising out of his many sins (v. 12). He had praised God for His loyal love and truth in the past (v. 10). Now he counted on those qualities to sustain him in the future (v. 11).
40:13-15 David cried out for quick deliverance. As the Lord's anointed who was serving Him sacrificially with a pure heart, the psalmist could make such a request boldly.
40:16 A speedy deliverance from his enemies would move the people of Israel to rejoice, feel encouraged, and praise the Lord.
40:17 The Lord's living sacrifice cried out again in conclusion that the One to whom he looked for help would save him soon.
Believers should present themselves as living sacrifices to the Lord with a willing heart because of His grace to them. Having done so we can appeal to Him for help against our spiritual enemies and expect His aid. Nevertheless we should base our appeal on what will glorify God.93
