Prophesying the restoration from exile (Isaiah 61), Isaiah says that at teh return the mourners in Zion will be comforted.  That is filled out as a triple gift (v. 3):

1. Beauty for ashes

2. Oil of joy for mourning

3. Garments of praise for spirit of heaviness

Several observations on these gifts.

1. The first gift uses a pun.  Beauty is pe’er , while ashes is ‘epher .  The second word inverts the first two consonants of the first word.  Thus, the verbal form of the word embodies the reversal involved in substituting beauty for ashes.

2. The three gifts follow the ordination rite for priests.  ”Beauty” is not the same word as that found in Exodus’ “garments of glory and beauty,” but it is a synonym, and it is used for the headgear of priests in Exodus 39:28.  Removing ashes, further, implies washing, which is the first stage of ordination.  Then Aaron and his sons are anointed with oil before being invested with the garments of glory and beauty.  Isaiah is describing the restoration of Judah as a as a re-investiture, re-ordination to priesthood (cf. v. 6).

3. The gifts of beauty, oil, garments form “trees of righteousness.”  We can think of this first in terms of literal trees.  Imagine a burnt stump of a tree.  What would it take to restore that stump to treehood?  Isaiah describes this as a threefold process: The ashes become wood, the tree is anointed (therefore, it is an “oil tree,” olive tree perhaps), and it is clothed in a robe of leaves.  Oil trees belong in the inner sanctuaries of the temple: The door of the Most Holy Place is made of oil wood, as are the cherubim that overarch the ark.

4. In context, the “trees of righteousness” are people.  By going through a re-ordination ritual, the people become anointed trees, Yahweh’s planting, presumably in the house of Yahweh.  The imagery suggests that Isaiah conceives of “tree” as a suitable symbol of “priest,” and that connects in various directions: Aaron was confirmed as priest when his staff budded like an almond tree; Psalm 92 speaks of trees planted in the house of Yahweh; the walls of the temple are carved with palm trees.  The temple is a grove, and in the temple are men like trees walking, the priests who serve Yahweh in His house.