# has put us apostles on display

God has displayed the apostles just like prisoners who are at the end of a Roman military parade. 

# like men sentenced to death

God put the apostles on display like men who are about to be executed. 

# to the world—to angels, and to human beings

Possible meanings are 1) "the world" consists of both supernatural ("angels") and natural ("human beings") or 2) the list consists of three items: "to the world, to angels, and to human beings."