Title and Authorship:
Psalm 16 is traditionally attributed to King David, as indicated in the superscription, "A Miktam of David." The term "Miktam" is of uncertain meaning, though it is often understood to denote a type of musical or liturgical term, possibly indicating a golden or precious composition. David, known as the "sweet psalmist of Israel" (2 Samuel 23:1), is credited with many psalms that express deep trust in God amidst various life circumstances.

Theme and Purpose:
Psalm 16 is a profound expression of trust and confidence in the Lord. It is a declaration of faith, highlighting the psalmist's reliance on God for protection, guidance, and ultimate joy. The psalm is often categorized as a psalm of confidence or trust, and it is noted for its messianic implications, particularly in its latter verses.

Structure and Content:

1. Verses 1-2: A Plea for Preservation and Declaration of Trust
The psalm opens with a plea for divine protection: "Preserve me, O God, for in You I take refuge" (Psalm 16:1). David immediately affirms his trust in the Lord, acknowledging that apart from God, he has no good thing. This sets the tone for the entire psalm, emphasizing the psalmist's complete dependence on God.

2. Verses 3-4: The Company of the Saints and Rejection of Idolatry
David expresses delight in the "saints in the land" (Psalm 16:3), indicating his fellowship with those who are faithful to God. In contrast, he rejects the practices of those who pursue other gods, stating, "Their sorrows will multiply who chase after other gods" (Psalm 16:4). This highlights the exclusivity of worship and devotion to the Lord.

3. Verses 5-6: The Lord as Inheritance and Portion
The psalmist acknowledges the Lord as his chosen portion and cup, signifying that God is his sustenance and inheritance. "The boundary lines have fallen for me in pleasant places; surely my inheritance is delightful" (Psalm 16:6). This imagery reflects the security and satisfaction found in a life devoted to God.

4. Verses 7-8: Guidance and Stability
David praises the Lord for His counsel and instruction, even in the night seasons. "I have set the LORD always before me. Because He is at my right hand, I will not be shaken" (Psalm 16:8). This verse underscores the stability and confidence that come from a life centered on God.

5. Verses 9-11: Joy, Security, and the Path of Life
The psalm culminates in a triumphant declaration of joy and security: "Therefore my heart is glad and my tongue rejoices; my body also will rest secure" (Psalm 16:9). The assurance of God's presence leads to the promise of eternal life, as David proclaims, "You will not abandon my soul to Sheol, nor will You let Your Holy One see decay" (Psalm 16:10). This verse is often cited in the New Testament as a prophecy of Christ's resurrection (Acts 2:25-28; 13:35-37). The psalm concludes with the affirmation of the "path of life" and the "fullness of joy" found in God's presence (Psalm 16:11).

Messianic Significance:
Psalm 16 holds significant messianic implications, particularly in verse 10, which is interpreted in the New Testament as a prophecy concerning the resurrection of Jesus Christ. The apostle Peter, in his sermon at Pentecost, cites this psalm to affirm that David foresaw the resurrection of the Messiah, who would not be abandoned to the grave nor see corruption (Acts 2:25-31).

Theological Insights:
Psalm 16 offers rich theological insights into the nature of trust in God. It emphasizes the exclusivity of worship, the joy of fellowship with the faithful, and the assurance of divine guidance and protection. The psalmist's confidence in God's provision and the hope of eternal life resonate with the core tenets of faith, underscoring the belief in God's sovereignty and the promise of resurrection.

Application for Believers:
For believers, Psalm 16 serves as a model of unwavering trust and devotion to God. It encourages a life of holiness, fellowship with other believers, and a rejection of idolatry. The psalm invites believers to find their ultimate joy and security in God's presence, looking forward to the eternal life promised through Christ's resurrection.