1 Corinthians 1:4-8
"I thank my God always on your behalf, for the grace of God which is given you by Jesus Christ; That in every thing ye are enriched by him, in all utterance, and in all knowledge; Even as the testimony of Christ was confirmed in you: So that ye come behind in no gift; waiting for the coming of our Lord Jesus Christ: Who shall also confirm you unto the end, that ye may be blameless in the day of our Lord Jesus Christ."
Paul told the Corinthians that they came behind in no gift, and he dedicated part of this epistle to the proper use of the same.
Later on, he told these same Corinthians to examine themselves to see if they were even in the faith.
2 Corinthians 13:5
"Examine yourselves, whether ye be in the faith; prove your own selves. Know ye not your own selves, how that Jesus Christ is in you, except ye be reprobates?"