"Then the eyes of the blind shall be opened, and the ears of the deaf shall be unstopped. Then shall the lame man leap as an hart, and the tongue of the dumb sing: for in the wilderness shall waters break out, and streams in the desert." - Isaiah 35:5,6
To be holy is to display His nature. He is undefiled and without impurity and He desires us to be the same.
In the Complete Word Study Dictionary, holiness in
Isaiah 35:8 means, "a holy thing and sacredness....