Psalms 15:2

2.He that walketh in integrity. Here we should mark, that in the words there is an implied contrast between the vain boasting of those who are only the people of God in name, or who make only a bare profession of being so, which consists in outward observances, and this indubitable and genuine evidence of true godliness which David commends. But it might be asked, As the service of God takes precedence of the duties of charity towards our neighbors, why is there no mention here made of faith and prayer; for, certainly, these are the marks by which the genuine children of God ought to have been distinguished from hypocrites? The answer is easy: David does not intend to exclude faith and prayer, and other spiritual sacrifices; but as hypocrites, in order to promote their own interests, are not sparing in their attention to a multiplicity of external religious observances, while their ungodliness, notwithstanding, is manifested outwardly in the life, seeing they are fall of pride, cruelty, violence, and are given to deceitfulness and extortion, - the Psalmist, for the purpose of discovering and drawing forth into the light all who are of such a character, takes the marks and evidences of true and sincere faith from the second table of the law. According to the care which every man takes to practice righteousness and equity towards his neighbors, so does he actually show that he fears God. David, then, is not here to be understood as resting satisfied with political or social justice, as if it were enough to render to our fellow-men what is their own, while we may lawfully defraud God of his right; but he describes the approved servants of God, as distinguished and known by the fruits of righteousness which they produce. In the first place, he requires sincerity; in other words, that men should conduct themselves in all their affairs with singleness of heart, and without sinful craft or cunning. Secondly, he requires justice; that is to say, that they should study to do good to their neighbors, hurt nobody, and abstain from all wrong. Thirdly, he requires truth in their speech, so that they may speak nothing falsely or deceitfully. To speak in the heart is a strong figurative expression, but it expresses more forcibly David’s meaning than if he had said from the heart. It denotes such agreement and harmony between the heart and tongue, as that the speech is, as it were, a vivid representation of the hidden affection or feeling within.