This psalm refers to a single subject, but that the most important which can come before the human mind. It is the question. Who is truly religious? who will enter heaven? who will be saved? The psalm contains a statement of what real religion is; one of the most explicit and formal of the statements which we have in the Old Testament on that subject. The form in which the matter is presented is that of a question in the first verse, and of the answer to that question in the other verses of the psalm.
I. The question. Psalm 15:1. The question is, who shall be permitted to reside with God in his tabernacle? who shall be entitled to the privilege of dwelling on his holy hill (that is, Zion, regarded as the dwelling-place of God, and the emblem of heaven)? In other words, who has such a character as to be entitled to hope for the favor and friendship of God?
II. The answer, Psalm 15:2-5. The answer embraces the following particulars:
(1) The man who is upright, just, honest, truthful, Psalm 15:2.
(2) The man who treats his neighbor properly; who does not slander or reproach him; who does not readily listen to calumnious reports in regard to him, Psalm 15:3.
(3) The man who regards the righteous and the wicked as they should be regarded; who looks with proper disapprobation on all who are "vile" in their character, and with true respect on all who fear the Lord, Psalm 15:4.
(4) The man who is faithful to an engagement, though it proves to be against his own interest, Psalm 15:4.
(5) The man who does not take advantage of the necessities of others, who does not put out his money "to usury," and who, if a magistrate, does not take a bribe to induce him to condemn the innocent, Psalm 15:5.
These are characteristics of true religion everywhere, and it is as true now as it was when this psalm was composed that it is only those who possess this character who have a right to regard themselves as the friends of God, or who have a well-founded hope of dwelling with him in heaven.
The psalm purports, in the title, to be "A Psalm of David." It is not known on what occasion it was written, nor is it material to know this in order to understand the psalm. It has been supposed by some that it was composed on the occasion when the ark was carried up from the house of Obed-edom (2-Samuel 6:12 ff), but there is nothing in the psalm itself which should lead us to refer it to that occasion, or to any other special occasion. It seems rather - like Psalm 1:1-6 - to be adapted to all times and all places. It contains a general illustration of the nature of true religion, and there has been no state of things in the world in which such a psalm might not be appropriately composed; there is none in which it may not be appropriately read and pondered.

The important question answered, Who is a proper member of the Church militant? and who shall finally join the Church triumphant? Verse Psalm 15:1 contains the question; Psalm 15:2-5, the answer.
The title, מזמור לדוד mizmor ledavid, a Psalm of David, has nothing in it particularly worthy of notice. If it were a Psalm composed during the captivity, relating to their return and settlement in their own land, with the restoration of their temple service and all the ordinances of God, and a description of the persons who should then be considered Israelites indeed, the name of David is improperly prefixed. But the subject is of the most general utility, and demands the most solemn and serious attention of all men who profess to believe in the immortality of the soul.

INTRODUCTION TO PSALM 15
A Psalm of David. As in the preceding psalm, according to Theodoret, the salvation of the inhabitants of Jerusalem is foretold, and the liberty of the captives; so in this advice is given to them, and the life they ought to live proposed, who should share in such benefits.

The way to heaven, if we would be happy, we must be holy. We are encouraged to walk in that way.

The Conditions of Access to God
The preceding Psalm distinguished דור צדיק, a righteous generation, from the mass of the universal corruption, and closed with a longing for the salvation out of Zion. Psalm 15:1-5 answers the question: who belongs to this דור צדיק, and whom shall the future salvation avail? Psalm 24:1-10, composed in connection with the removal of the Ark to Zion, is very similar. The state of mind expressed in this Psalm exactly corresponds to the unhypocritical piety and genuine lowliness which were manifest in David in their most beauteous light on that occasion; cf. Psalm 15:4 with 2-Samuel 6:19; Psalm 15:4 with 2-Samuel 6:21. The fact, however, that Zion (Moriah) is called simply הר הקּדשׁ in Psalm 15:1, rather favours the time of the Absolomic exile, when David was cut off from the sanctuary of his God, whilst it was in the possession of men the very opposite of those described in this Psalm (vid., Psalm 4:6). Nothing can be maintained with any certainty except that the Psalm assumes the elevation of Zion to the special designation of "the holy mountain" and the removal of the Ark to the אהל erected there (2-Samuel 6:17). Isaiah 33:13-16 is a fine variation of this Psalm.