G4731–στερεός–stereos

sure, nevertheless, hath the foundation of God stood, having this seal, `The Lord hath known those who are His,' and `Let him depart from unrighteousness -- every one who is naming the name of Christ.'

στερεὸς stereos “the firm”

for even owing to be teachers, because of the time, again ye have need that one teach you what `are' the elements of the beginning of the oracles of God, and ye have become having need of milk, and not of strong food,

στερεᾶς stereas “of solid”

and of perfect men is the strong food, who because of the use are having the senses exercised, unto the discernment both of good and of evil.

στερεὰ sterea “solid”

whom resist, stedfast in the faith, having known the same sufferings to your brotherhood in the world to be accomplished.

στερεοὶ stereoi “firm”