Hormah
i.e. utter destruction.

serpent
(See Scofield "") . The serpent is a symbol of sin judged; brass speaks of the divine judgment, as in the brazen altar See Scofield "", note (2) and self-judgment, as in the laver of brass. The brazen serpent is a type of Christ "made sin for us" ; John 3:14; John 3:15; 2 Corinthians 5:21 in bearing our judgment. Historically, the moment is indicated in the cry: "My God, My God, why hast Thou forsaken Me?" Matthew 27:46.

Then Israel
The spiritual order here is beautiful:
(1) atonement Numbers 21:8; Numbers 21:9; John 3:14; John 3:15
(2) water, symbol of the Spirit bestowed Numbers 21:16; John 7:37-39.
(3) joy Numbers 21:17; Numbers 21:18; Romans 14:17.
(4) power Numbers 21:21-24.