The apostle wrote to the Christians at Rome: “Quit being fashioned after this system of things, but be transformed by making your mind over.” (Ro 12:2) It was not the time period itself that set the fashion, pattern, or model for people of that time, but it was the standards, practices, manners, customs, ways, outlook, styles, and other features characterizing that time period. At Ephesians 2:1, 2 the apostle speaks of those to whom he writes as having been “dead in your trespasses and sins, in which you at one time walked according to the system of things [“following the way,” JB; “following the course,” RS] of this world.” In commenting on this text, The Expositor’s Greek Testament (Vol. III, p. 283) shows that time is not the sole or prime factor here expressed by ai·onʹ. In support of the rendering of ai·onʹ by “course,” it says: “That word conveys the three ideas of tenor, development, and limited continuance. This course of a world which is evil is itself evil, and to live in accordance with it is to live in trespasses and sins.”​—Edited by W. Nicoll, 1967.

The worldly ai·onʹ, or system of things, had been in existence even before the introducing of the Law covenant. It continued contemporaneously with the ai·onʹ of that covenant, and it endured beyond the end of the ai·onʹ, or state of affairs, that the Law covenant had introduced. The worldly ai·onʹ evidently began sometime after the Flood, when an unrighteous way of life developed, one characterized by sin and rebellion against God and his will. Hence, Paul could also speak of “the god of this system of things” as blinding the minds of unbelievers, an evident reference to Satan the Devil. (2Co 4:4; compare Joh 12:31.) Primarily, Satan’s dominion and influence have molded the worldly ai·onʹ and given it its distinctive features and spirit. (Compare Eph 2:1, 2.) Commenting on Romans 12:2, The Expositor’s Greek Testament (Vol. II, p. 688) says: “Even apparent or superficial conformity to a system controlled by such a spirit, much more an actual accommodation to its ways, would be fatal to the Christian life.” Such worldly ai·onʹ was to continue long after the apostle’s day.