From the last three verses of Psalm 16, it is clear that David expected eternal life. He knew that he would be resurrected. The path of life
refers to eternal life.
Psalm 16 is also prophetic in nature. Peter preached on this Psalm after the outpouring of the Holy Spirit (Acts 2:29–31) and Paul in the synagogue in Antioch (Acts 13:35–37). Peter quoted Psalm 16 as proof of Jesus’ resurrection. He used it to demonstrate that David was not only speaking of himself but was also anticipating the coming of Jesus. Jesus' resurrection guaranteed his resurrection.
The same is true of Paul’s address in the synagogue in Antioch. Both Peter and Paul did not intend to deny David’s resurrection, but to prove Jesus’ resurrection based on Psalm 16. The righteous know that they will die, but that they shall not remain dead. This expectation was fulfilled by Jesus—the firstfruits of those who have fallen asleep
(1 Corinthians 15:20). Together with David and the other faithful, we can place our hopes for eternity on the assurances of God.
11 You make known to me the path of life; in your presence there is fullness of joy; at your right hand are pleasures forevermore.