The Scofield Bible Commentary, by Cyrus Ingerson Scofield, [1917], at sacred-texts.com
Romans Chapter 16
mystery
(See Scofield) - (Mat 13:11).
The "mystery" here is the Church; (Eph 3:1-9).
obedience
See margin reference, (See Scofield) - (Rom 1:5).
Faith as a system, in contrast with law as a system.