1. O Lord! thou hast been our dwelling-place. In separating the seed of Abraham by special privilege from the rest of the human family, the Psalmist magnifies the grace of adoption, by which God had embraced them as his children. The object which he has in view in this exordium is, that God would now renew the grace which he had displayed in old time towards the holy patriarchs, and continue it towards their offspring. Some commentators think that he alludes to the tabernacle, because in it the majesty of God was not less conspicuous than if he had dwelt in the midst of the people; but this seems to me to be altogether out of place. He rather comprehends the whole time in which the Fathers sojourned in the land of Canaan. As the tabernacle had not yet continued for the space of forty years, the long duration here mentioned -- our dwelling-place from generation to generation -- would not at all be applicable to it. It is not then intended to recount what God showed himself to be towards the Israelites from the time that he delivered them from Egypt; but what their fathers had experienced him to be in all ages, even from the beginning. ² Now it is declared that as they had always been pilgrims and wanderers, so God was to them instead of a dwelling-place. No doubt, the condition of all men is unstable upon earth; but we know that Abraham and his posterity were, above all others, sojourners, and as it were exiles. Since, then, they wandered in the land of Canaan till they were brought into Egypt, where they lived only by sufferance from day to day, it was necessary for them to seek for themselves a dwelling-place under the shadow of God, without which they could hardly be accounted inhabitants of the world, since they continued everywhere strangers, and were afterwards led about through many windings and turnings. The grace which the Lord displayed in sustaining them in their wanderings, and shielding them with his hand when they sojourned among savage and cruel nations, and were exposed to injurious treatment at their hands -- this grace is extolled by Moses in very striking terms, when he represents God as an abode or dwelling-place to these poor fugitives who were continually wandering from one place to another in quest of lodgings. This grace he magnifies from the length of time during which it had been exercised; for God ceased not to preserve and defend them for the space of more than four hundred years, during which time they dwelt under the wings of his protection.

2. Before the mountains were brought forth. Moses designs to set forth some high and hidden mystery, and yet he seems to speak feebly, and, as it were, in a puerile manner. For who does not know that God existed before the world? This we grant is a truth which all men admit; but we will scarcely find one in a hundred who is thoroughly persuaded that God remains unchangeably the same. God is here contrasted with created beings, who, as all know, are subject to continual changes, so that there is nothing stable under heaven. As, in a particular manner, nothing is fuller of vicissitude than human life, that men may not judge of the nature of God by their own fluctuating condition, he is here placed in a state of settled and undisturbed tranquillity. Thus the everlastingness of which Moses speaks is to be referred not only to the essence of God, but also to his providence, by which he governs the world. Although he subjects the world to many alterations, he remains unmoved; and that not only in regard to himself, but also in regard to the faithful, who find from experience, that instead of being wavering, he is steadfast in his power, truth, righteousness, and goodness, even as he has been from the beginning. This eternal and unchangeable steadfastness of God could not be perceived prior to the creation of the world, since there were as yet no eyes to be witnesses of it. But it may be gathered a posteriori; for while all things are subject to revolution and incessant vicissitude, his nature continues always the same. There may be also here a contrast between him and all the false gods of the heathen, who have, by little and little, crept into the world in such vast numbers, through the error and folly of men. But I have already shown the object which Moses has in view, which is, that we mistake if we measure God by our own understanding; and that we must mount above the earth, yea, even above heaven itself, whenever we think upon him.