# when his time will come

"when he will die" or "when the time of his death will come"

# fish are caught ... birds are caught ... the children of human beings are ensnared

This speaks in the same way that people catch animals and kill them when they do not expect it.

# the children of human beings are ensnared by evil times

"evil times are coming upon the children of human beings"

# that suddenly fall upon them

"at times when they do not expect them to happen"