You do not know what you are asking: To share in his glory, they must also share in his suffering as servants.
drink the cup: Drinking from a cup often represents suffering and death (Psalm 75:8; Isaiah 51:17, 22; Jeremiah 25:15; 49:12; Lamentations 4:21; see also Mark 14:24, 36).
The baptism of suffering points back to the full commitment Jesus showed to God’s calling at his baptism. It also points to the believer’s union with Jesus in his death, burial, and resurrection through baptism (Romans 6:3–5; Colossians 2:12).