This can be stated in active form. Alternate translation: "Its shade covered the mountains, its branches the cedars of God" (See: [[rc://en/ta/man/translate/figs-activepassive]])
"and the cedars of God were covered by its branches," which copies the verb from the previous sentence. This can be stated in active form. Alternate translation: "and its branches covered the cedars of God" (See: [[rc://en/ta/man/translate/figs-ellipsis]] and [[rc://en/ta/man/translate/figs-activepassive]])
Possible meanings are 1) "the highest cedar trees," the cedar trees that grew on the "mountains" in the land of Lebanon north of Israel, or 2) "God's own cedar trees."