In verse 7 the pilgrims demand that the Temple gates be opened to admit entrance to the LORD, who is probably represented by the Covenant Box, which is being carried in by Levites. (In 2 Sam 6.2 the Covenant Box bears the name of the LORD Almighty; and in 1 Sam 4.21, when the Covenant Box is captured by the Philistines, God’s glory departs from Israel.) From inside the Temple the priests (verse 8a) ask who demands entry, to which the procession replies (verse 8b-c).
The poetic language, your heads, O gates … O ancient doors, refers to the Temple gates. It is not certain what the word heads means, if indeed it refers poetically to some part of the gates; New American Bible takes it to mean “the lintels,” the horizontal pieces above the gates; Jerusalem Bible “arches.” Gates in line a and doors in line b are two different ways of speaking of the same thing, that is, the Temple gates. Some translations therefore combine the two and have only “Open wide, eternal gates!” or something similar (see Die Bibel im heutigen Deutsch, Biblia Dios Habla Hoy). Commentators suggest that the meaning is that the gates are too small for such a great king, the LORD, to enter, and so they are commanded to raise their lintels in order to make room for the king to enter. Most translations have the idea of “raising” or “lifting up,” but Good News Translation has used the more natural expressions “Fling wide … open,” which are directed not to the gates themselves but to the Levites in the Temple who were responsible for opening them. It should be noted that the Hebrew expression “lift up the head” can mean “rejoice.” The translator must decide if the gates are to be opened or if they are to rejoice. In many languages the decision will be made in favor of the former, since inanimate objects such as gates do not rejoice.
The ancient doors points to the fact that Jerusalem was already an ancient city when David captured it. Some, however, take the word to mean “eternal,” reflecting the idea that the gates of the sanctuary were the earthly counterpart of the heavenly dwelling of God, and that when the earthly gates were opened the heavenly gates also opened.
The King of glory (verses 7c, 8a) is the majestic, mighty, victorious king. For glory as an attribute of kings, see comments on 21.5. In languages where “glory” means life in heaven, the genitive phrase King of glory may suggest that the title means “King of heaven.” But of glory has the force of an adjective, “glorious.” Die Bibel im heutigen Deutsch has “mightiest king … mighty king.”
Quoted with permission from Bratcher, Robert G. and Reyburn, William D. A Handbook on the Book of Psalms. (UBS Helps for Translators). New York: UBS, 1991. For this and other handbooks for translators see here .