their god is their belly: This phrase may refer to their greed, sexcual desires, or self-interest (compare Romans 16:18).
their glory is in their shame: This most likely refers to immoral behavior, not to pride in circumcision.
Eternal destruction is God's ultimate judgment for those who reject Christ and live selfish, sinful lives (see 2 Thessalonians 1:8–9; compare Philippians 1:28; Matthew 7:13; Romans 9:22; 1 Corinthians 1:18; 2 Thessalonians 2:10; 1 Timothy 6:9; 2 Peter 2:3, 13; Jude 1:10; Revelation 11:18).
their minds are set on earthly things: They cannot see beyond this life (compare John 12:25; 1 John 2:15–17).