Midrash su I Cronache 16:33

Our sages of blessed memory said: And the middle bar in the midst of the boards (ibid., v. 28). They went down to Egypt with Jacob our patriarch, for it was difficult for them to bolt the boards from end to end. Furthermore, these cedars intoned a song before the Lord. Whence do we know that they sang a song? Because it is written: Then shall all the trees of the world sing for joy before the Lord (Ps. 96:12). The word then is employed in reference to a song, as is said: Then sang Moses (Exod. 15:1). When did that occur? At the time the Sanctuary was erected from them. The Holy One, blessed be He, commanded Moses concerning the Tabernacle: And thou shalt make the boards for the Tabernacle of acacia wood, standing up (ibid. 26:15). “Thou shalt make boards” is not written here, but rather Thou shalt make the boards standing, that is, they should use those boards that their fathers had previously prepared for them. The word standing refers to the boards that were already in existence.

Another interpretation of, "And you shall take for yourselves on the first day" (Leviticus 23:40). This is [the understanding of] that which is written (Psalms 96:12), "The fields exult and everything in them": "The fields exult" - that is this world, as it is stated (Genesis 4:8), "and it was when they were in the field." "And everything in them" - these are the creatures, like you say (Psalms 24:1), "The earth is the Lord’s and all that it holds, [the world and its inhabitants]." "Then shall the trees of the forest shout for joy" (I Chronicles 16:33). Rabbi Acha said, "[Here it states,] 'the forest,' [but in Psalms 96:12 above, it states,] 'and all the trees of the forest.' 'The forest' - those are the trees that produce fruit; 'all the trees of the forest' - those are the trees that do not produce fruit." In front of whom? "In front of the Lord" (Psalms 98:9). Why? "For He is coming," on Rosh Hashanah and Yom Kippur. To do what? "He will judge the world with righteousness, and its peoples with equity."