To appoint unto them that mourn in Zion, to give unto them beauty for ashes, the oil of joy for mourning, the garment of praise for the spirit of heaviness; that they might be called trees of righteousness, the planting of the Lord, that He might be glorified.
To appoint unto them that mourn in Zion: To appoint is to place, or set, as a permanent thing.
Beauty for ashes: This is a very specific embellishment. It refers to a fancy headdress; beautiful diadem; tiara; that all who mourn will be given a beautiful nuptial tiara instead of the ashes thrown on the head while in mourning.
The oil of joy for mourning: The oil of joy denotes that which expresses joy and happiness. Oil was employed on occasions of festivity and gladness but was done away in time of public calamity or grief.
The garment of praise for the spirit of heaviness: A garment expressing praise and gratitude instead of mourning and a spirit of heaviness, or a burdened spirit. The original word for “spirit of heaviness” usually meant “faint, feeble, weak.” It is used of a lamp going out, and eyes becoming dim. Here it refers to one who is depressed and faint.
Trees of righteousness: This refers to oaks or cedars by rivers of water.