With the exception of Heb. 13:6, the Greek verb “tharrheo” is found in the book of Second Corinthians (see 2 Cor. 5:6, 8; 7:16; 10:1-2).  This verb meant “to be confident,” “to be of good courage,” or “to be bold.”

In 2 Cor. 7:16, this verb expresses Paul’s confidence “in the Corinthian church.  But in 10:1-2 the same word is used of the boldness with which he is determined to face those who oppose him in Corinth, though here he may be responding to an accusation that he shows boldness only when he does not have to deal with his opponents in person.  In 5:6, 8 Paul speaks of the confidence that he enjoys even in his life of suffering, for he is supported by the assurance that he has an eternal home with the Lord.  The letter to the Hebrews exhorts its readers to a sim. confidence as they face the necessity of holding out in a pagan environment that is hostile toward them (Heb. 13:6)” (Silva, 2:419).