What does Psalm 118:27 mean?

The beginning of this verse uses two important Hebrew words. The first is Yahweh, the name God used to identify Himself (Exodus 3:15). The second term is ēl', a generic term for power often implying a deity. The psalmist feels joy knowing that God has provided. What's given is described as "light." In the Old Testament, light symbolized truth and goodness (Psalm 27:1). Just as Jesus accepted public praise connecting Him to prophecy (Psalm 118:25–26; Matthew 21:9), He also referred to Himself as "the light of the world" (John 8:12). This strongly identified Him with the Lord God (Psalm 119:105; Isaiah 60:1).

The second half of this verse begins with a notoriously obscure Hebrew phrase. Some translations take this as a reference to strapping a feast-day sacrifice to the altar, which had "horns" on the four corners (Exodus 27:2). But this does not seem to have been part of the typical sacrificial process. Others suggest that sacrifices should be brought in large numbers, such that the awaiting animals were being held—tied—in every available space, including right up to the altar. Still others think this is simply a reference to binding an animal, then bringing it to the place of sacrifice. A few interpreters detect a reference to holding boughs; this may have been why those who applied this psalm to Jesus' triumphal entry (Psalm 118:25–26; Matthew 21:8–9) waved palm branches.