'Necessary' in the Bible

And he began to teach them that it was necessary [for] the Son of Man to suffer many [things] and to be rejected by the elders and the chief priests and the scribes, and to be killed, and after three days to rise.

They asked Him, saying, “Why do the scribes say that Elijah must come first [before the Messiah comes]?”

When you hear of wars and rumors of wars, do not be alarmed (frightened, troubled); these things must take place, but the end is not yet.

And he spake the more vehemently, 'If it may be necessary for me to die with thee -- I will in no wise deny thee;' and in like manner also said they all.