Easton's Bible Dictionary: M. G. Easton, M.A., D.D.

Surety

One who becomes responsible for another. Christ is the surety of the better covenant (Heb. 7:22). In him we have the assurance that all its provisions will be fully and faithfully carried out. Solomon warns against incautiously becoming security for another (Pr. 6:1-5, 11:15, 17:18, 20:16).