Genesis 3:1 (a) This is a type of Satan for he is so described in Revelation 12:9.

Numbers 21:6 (b) It is a type of sin in all of its terrible effect on the people.

Numbers 21:8 (a) It is a type of the Lord JESUS when He was made sin for us ( 2 Corinthians 5:21) as He hung on Calvary. (See John 3:14).

Matthew 7:10 (b) This is a symbol of a harmful, injurious thing which the Christian, in his ignorance, thinks is good and profitable. The Lord sees that he is mistaken in his request and so refuses to give it to him because He knows it would harm. GOD says "no" to the request.