en_tn/mrk/10/38.md

You do not know

"You do not understand"

drink the cup which I will drink

Here "cup" refers to what Jesus must suffer. Suffering is often referred to as drinking from a cup. Alternate translation: "drink the cup of suffering that I will drink" or "drink from the cup of suffering that I will drink from" (See: rc://en/ta/man/jit/figs-metaphor)

be baptized with the baptism with which I will be baptized

Here "baptism" and being baptized represent suffering. Just as water covers a person during baptism, suffering will overwhelm Jesus. Alternate translation: "endure the baptism of suffering which I will suffer" (See: rc://en/ta/man/jit/figs-metaphor)