like lambs to the slaughter

like a lamb to (the) slaughter

Without concern for what is to come (because one does not foresee the trouble ahead). This phrase comes from the Bible. When I did business with Michael, I was like a lamb to the slaughter—I had no idea he was such a criminal mastermind. The poor kid and his defense team weren't aware of what the prosecution had in store—it was like lambs to slaughter the moment the trial began.
See also: lamb, like, slaughter

like lambs to the slaughter

 and like a lamb to the slaughter
Fig. quietly and without seeming to realize the likely difficulties or dangers of a situation. Young men fighting in World War I simply went like lambs to the slaughter. Our team went on the football field like lambs to the slaughter to meet the league-leaders.
See also: lamb, like, slaughter