You may be referring to the phrase that was used in a sermon that “you have to be sold on the Way of Life” to be a true Christian.
When someone is called into the true Church of God, it is a unique calling from God, as we read in John 6:44 where Jesus said: “No one can come to Me unless the Father who sent Me draws him; and I will raise him up at the last day.” In fact, Jesus repeated this in verse 65 of the same chapter, prefacing His comments with: “I have said to you…,” and then reiterating that a calling from the Father was necessary.
Unfortunately, today there are those who say that they have been seeking God and join a church of their choice, but that is not a calling from God. It is a priceless privilege to be called by God at this time, and He places in His church those whom He chooses.
The Free Dictionary online describes the phrase “to be sold on something” as an idiom, and idioms are classified as figurative language which is the use of words in an unusual or imaginative manner. It describes the phrase as follows: