'Sound' in the Bible

holding -- according to the teaching -- to the stedfast word, that he may be able also to exhort in the sound teaching, and the gainsayers to convict;

this testimony is true; for which cause convict them sharply, that they may be sound in the faith,

And thou -- be speaking what doth become the sound teaching;

aged men to be temperate, grave, sober, sound in the faith, in the love, in the endurance;

discourse sound, irreprehensible, that he who is of the contrary part may be ashamed, having nothing evil to say concerning you.