Charles Ellicott Commentary Psalms 84:3

"Yea, the sparrow hath found her a house, And the swallow a nest for herself, where she may lay her young, Even thine altars, O Jehovah of hosts, My King, and my God." — Psalms 84:3 (ASV)

Sparrow. —Heb., tsippôr, which is found upwards of forty times in the Old Testament, and is evidently used in a very general way to include a great number of small birds. "Our common house-sparrow is found on the coast in the towns, and inland its place is taken by a very closely-allied species, Passer cisalpina" (Tristram, Natural History of the Bible, p. 202).

Swallow. —Heb. derôr, which by its etymology implies a bird of rapid whirling flight. (See Proverbs 26:2, where this characteristic is especially noticed.) The ancient versions take the word as cognate with "turtle-dove." In an appendix to Delitzsch’s Commentary on the Psalms, Dr. J. G. Wetzstein identifies the tsippôr with the ôsfur of the Arabs, a generic name for small chirping birds, and derôr with dûri, which is specific to the sparrow.

Even your altars. —Better, at or near your altars, though even if taken as in the Authorized Version, the meaning is the same. There is no real occasion for the great difficulty that has been made about this verse.

It is absurd indeed to think of the birds actually nesting on the altars; but it is quite probable that they were found in and about the Temple, just as in Herodotus (i. 159) we read of Aristodicus making the circuit of the temple at Branchidae, and taking the nests of young sparrows and other birds. (Compare the story in Aelian of the man who was slain for harming a sparrow that had sheltered in the temple of Aesculapius.) Ewald gives many other references, and among them one to Burckhardt showing that birds nest in the Kaaba at Mecca.

The Hebrew poetic style is not favourable to simile, or the psalmist would have written (as a modern would), "As the birds delight to nest at your altars, so do I love to dwell in your house."