'Uncertain' in the Bible

whether Paul or Apollos or Cephas (Peter) or the world or life or death or things present or things to come; all things are yours,

For if someone sees you, a person having knowledge, eating in an idol’s temple, then if he is weak, will he not be encouraged to eat things sacrificed to idols [and violate his own convictions]?

For if the trumpet give an uncertain sound, who shall prepare himself to the battle?