The Pulpit Commentary
The earth is the Lord's, and the fulness thereof. God's glory was set forth in Psa_19:1-14. from a consideration of the heavens (Psa_19:1-6); here it is manifested from the other half of creation—the earth. The whole earth, and all its fnlness, is his. He made it, and he remains its sole Owner and Master. There is no inferior δημιουργός, as some believed, who framed it and governs it. All its marvels, all its beauty, all its richness, proceed from God alone. The world, and they that dwelt therein. "The world" (תֵּבֵל) seems to be here synonymous with" the earth" (הָאָרֶץ). Not only do its material products belong to God, but its inhabitants also.

The Pulpit Commentary
For he hath founded it upon the seas, and established it upon the floods (comp. Gen_1:9). God has established the earth above the seas and floods, causing it to "appear," and thus making it a fitting habitation for man. Hence his right of property in the earth and in all the dwellers on it. They exist through his providential care (comp. Psa_104:6-9).

The Pulpit Commentary
Who shall ascend into the hill of the Lord? The second strophe opens with one of David's sudden transitions. Who is worthy to be brought into contact with a God of such might and glory? Who shall ascend into his hill? God's "hill" is, in reality, the highest heaven, wherein he has his dwelling-place. Its representative on earth was, at this time, the Mount Zion, where it was already determined in the Divine counsels that the temple should be built, and whither David was now about to transfer the ark of the covenant (see the introductory paragraph). David asks the question as a warning to the Levites, whom he was about to employ in the transport of the ark, that they might purify themselves in heart and soul before venturing to take part in the solemn ceremony. Or who shall stand in his holy place? Who, i.e; shall stand and minister inside the tabernacle, when the ark has been placed therein, and it has thus become, in a special sense, God's holy place?

The Pulpit Commentary
He that hath clean hands. He whose hands are free from acts of sin (comp. Psa_15:2-5), and not only so, but he who hath also a pure heart, since the heart is the source of all evil (Mat_15:19, Mat_15:20), and wrongful words and wicked acts are the necessary results of the heart being impure. "God's demands upon his people," as Hengstenberg observes, "go beyond the domain of action. Those only see him—those only are fit to ascend into his hill—who have a pure heart." Who hath not lifted up his soul unto vanity; i.e. who has not lusted after vain and worthless things, whose desires are subdued, brought into captivity to the Law of God, and kept under strict control. This is really implied in purity of heart. Nor sworn deceitfully. False swearing is the worst—or, at any rate, one of the worst—sins of the tongue. The psalmist means to say that a man is not fit to draw near to God unless he is righteous in act, in thought, and in word.

The Pulpit Commentary
He shall receive the blessing from the Lord; rather, blessing, without the article. On the pure in thought, word, and act, God's blessing is sure to rest (see Mat_5:8). And righteousness from the God of his salvation. To the man who comes to God with an honest and true heart, God will give additional graces, such as justification, assurance, perseverance, unwavering hope, perfect charity.

The Pulpit Commentary
This is the generation of them that seek him. Men with this character impressed upon them are the "generation," the stamp of men, whom God will recognize and accept as his worshippers, true seekers after him. That seek thy face, O Jacob. The LXX. have, Ζητούντων τὸ πρόσωπον τοῦ Θεοῦ Ἰακώβ, whence some suppose אלהי to have fallen out of the Hebrew text. This, no doubt, is possible, and removes all difficulty. But it is better to loose a Gordian knot than to cut it. We may keep the present text, and obtain a satisfactory sense, by regarding "Jacob" as grammatically in apposition with "generation,'' and translating, "This is the generation of them that seek him—that seek thy face—even Jacob." All they are not Israel who are of Israel (Rom_9:6). The true Jacob consisted of those Israelites who answered to the character described in Psa_24:4. Selah. A break, or pause, here occurred, while the procession of Levites advanced to the very gates of the sanctuary. Then the strain was resumed—the choir being divided into two parts, which sang antiphonally.

The Pulpit Commentary
Lift up your heads, O ye gates. So sang one half of the choir, calling upon the gates to throw themselves wide open to their full height, that free entrance might he given to the approaching sacred fabric. And be ye lift up, ye everlasting doors. Pleonastic, But giving the emphasis of repetition, and adding the epithet "everlasting," because the tabernacle was viewed as about to be continued in the temple, and the temple was designed to be God's house "for ever" (1Ki_8:13). And the King of glory shall come in. God was regarded as dwelling between the cherubim on the mercy-seat, where the Shechinah from time to time made its appearance. The entrance of the ark into the tabernacle was thus the "coming in of the King of glory."

The Pulpit Commentary
Who is this King of glory? The other half of the choir, acting as keepers of the doors, inquires, as if ignorant of the motive and character of the procession, "Who is this King of glory?"—who is it to whom ye give this high-sounding appellation, and to whom ye require us to open? And the reply follows from the previous speakers. The Lord strong and mighty, the Lord mighty in battle. It is Jehovah, the Strong and Mighty One-strong in himself, mighty in his acts, mighty especially in battle; whom ye may therefore be glad to receive among you as your Defence. It is this King for whom we demand admission.

The Pulpit Commentary
Lift up your heads, O ye gates; even lift them up, ye everlasting doors; and the King of glory shall come in. A repetition of Psa_24:7, the first part of the choir reiterating its challenge.

The Pulpit Commentary
Who is this King of glory? The second part of the choir reiterates its question, as though not yet quite understanding. "Who is he, this King of glory?" and the first, slightly varying its answer, replies, The Lord of hosts, he is the King of glory. The epithet, "Lord of hosts" well known at the time (1Sa_1:11; 2Sa_5:10; 2Sa_6:2; 2Sa_7:18, 2Sa_7:26, 2Sa_7:27, etc.), made all clear, and, the gates being thrown open, the ark was brought in, and set in its place in the midst of the tabernacle (2Sa_6:17). It has been generally recognized that the reception of the ark into the tabernacle on Mount Zion typified the entrance of our Lord into heaven after his ascension, whence our Church appoints this psalm as one of those to be recited on Ascension Day.