What does Psalm 15:2 mean?

The person who is the Lord's guest in His tabernacle (Psalm 15:1) proves the genuineness of his faith by leading a blameless life and speaking truthfully. The term "blameless" is often misunderstood to imply "sinless;" it means being sincere and free of any legitimate charge of sinful conduct, in so far as that's possible for a fallible person (1 John 1:8–10). At the beginning of the church age, the congregation at Jerusalem was instructed to choose seven men to oversee the church's welfare program. One of the required qualifications for these men was that of being "of good repute" (Acts 6:3). Paul exhorted the Philippian believers to be "blameless and innocent, children of God without blemish in the midst of a crooked and twisted generation" (Philippians 2:15).

David also refers to this person as one who "speaks truth in his heart." Honesty and truthfulness are necessary parts of personal integrity. That not only applies to the world, at large, but to one's own thoughts and emotions. The Hebrew concept of "the heart" is not purely emotional. Terms translated as "heart" and "mind" in ancient writing are more closely related than they are in modern language. The righteous person is not only honest with others, and about others, but with and about himself, as well.

Clearly, the person who anticipates dwelling with the Lord in heaven demonstrates a righteous life on earth. Having received salvation by grace through faith (Ephesians 2:8–9), he performs good deeds as a natural outcome and visible evidence of that salvation (Ephesians 2:10; Philippians 2:12–13).