en_tn/mrk/11/31.md

If we say, 'From heaven,'

This refers to the source of the baptism of John. Alternate translation: "If we say, 'It was from heaven,'" (See: rc://en/ta/man/jit/figs-ellipsis)

From heaven

Here "heaven" refers to God. See how you translated this in Mark 11:30. Alternate translation: "From God" (See: rc://en/ta/man/jit/figs-metonymy)

not believe him

The word "him" refers to John the Baptist.