Let's Know
The words invite further consideration of his choices - 'let us stop and ponder' (cf. Bevington, fn l.17, p. 91). It exposes the flaw in his demonstration: if he commits suicide, the murder of his son would remain unavenged, and also marks the final shift in Hieronimo's pursuit of justice: having found social and divine unsatisfactory/unattainable, he decides in favour of personal justice.