1 Corinthians 14:8

For if the trumpet give an uncertain voice, who shall prepare himself for war?

The meaning of this is exactly the same as in 1 Corinthians 14:7, the repetition of the thought using another illustration was for emphasis. Uninterpreted tongues were as disastrous as the efforts of a military bugler whose unintelligible blasts could not be distinguished either as a call to charge, a call to retreat, or a call to go to bed!