Matthew Henry

Henry emphasizes the dual role of God as both strength and shield. He notes that a "shield" is meant to protect us from harm, and therefore, it signifies God's safeguarding presence in the lives of the faithful. The psalmist reflects a deep dependence on God, stating that his heart finds confidence in this divine assistance.

Henry also points out the emotional state of the believer; joy and song are natural responses to the realization of divine help. This joy arises not merely from what God does but from who He is—a personal strength and protector. The act of praising God is both a declaration of gratitude and an acknowledgement of His essential nature.

Albert Barnes

Barnes expounds the notion of trust inherent in this verse. He defines trust in God as a firm reliance on His goodness and faithfulness. The phrase "my heart trusts in him" indicates that true trust flows from the depths of one’s heart, a heart that has known God's faithfulness in times of trouble.

He also draws attention to the personal aspect of this relationship. The use of "my" emphasizes that each believer has a personal relationship with God, making the strength and protection He offers deeply individual. The result of this trust, according to Barnes, is a sense of joy that culminates in worship—symbolized through song. This reflects an intimate joy that is not contingent upon circumstances but is rooted in God’s character.

Adam Clarke

Clarke elaborates on the metaphor of God as both strength and shield, suggesting a multi-faceted image of God's protection. He notes that "strength" signifies internal fortitude provided by the Lord, while "shield" represents external protection against adversaries.

He also highlights the progression of emotion in this verse—beginning with trust, leading to help, and resulting in joy. Clarke interprets the joyful leaping of the heart as an overflow of praise and identifies the act of singing as a vital expression of one's faith. The song is not only a reaction to God’s help but also an affirmation of the believer's steadfast hope in Him.

Conclusion

This verse invites not only a recognition of God's characteristics as strength and shield but also challenges the believer to engage deeply in trust and reliance upon Him. It serves as an encouragement to maintain a posture of praise regardless of circumstances, understanding that genuine joy flows from intimate communion with God and assurance in His provision.