What did Les identify as the secret connected with the church?
The church and all events connected with it were the secret kept in the mind of God, not revealed until God saw fit. This mystery, a word unique to Paul's writings, refers to that hidden secret, as stated in Romans 11:25.
Les explains that in Romans 11:25, Paul introduces the word 'mystery,' which is unique to his writings and refers to a secret kept in the mind of God. He stresses that the church and all events connected with the church are that secret—hidden in God's mind and not revealed until God saw fit. This follows Paul's discussion of Israel's future and her grafting in again, showing the church was a separate, previously unrevealed program.
For I would not, brethren, that ye should be ignorant of this mystery, lest ye should be wise in your own conceits; that blindness in part is happened to Israel, until the fulness of the Gentiles be come in.