He calls the decree the "pristine law" and the "compendia of discipline" that relaxes the OT law but binds 'from the more noxious' actions that were also prohibited by the OT. He believes the decree is "ever immutable" and exists "in perpetuity." Tertullian affirms that it "will cease [only] with
the world."
Does Tertullian interpret the decree as the basis of a new, Christian legalism? If by "legalism" we mean becoming a Christian, earning God's favor by observing laws. the answer. is negative. It would be a mistake to interpret any version of the decree, including Tertullian's, as legalism in this sense. The thrust of the earlier part of the record of the Jerusalem Council in Acts 15 rejects that possibility. Salvation is clearly defined as a state received "by faith" (v 9) "through grace" (v 11). It is true that the provisions of the decree are called "necessary things" (15:28), but the letter containing them concludes with the statement that they are "necessary" in order that the Gentiles "will do well" (15:29). There is no hint in Acts that the decree was considered necessary for salvation, and Tertullian does not appear to introduce any such idea into his discussion of it.
"Legalism" may also refer to precise definition and regulation of the conduct of one already a Christian through stated ordinances. Tertullian's insistence upon the decree as a "compendium of discipline" and an irrevocable law for believers seems to indicate that he did regard it as the standard for a Christian legalism of this sort.
Scott, J. Julius, Jr. “Textual Variants of the Apostolic Decree and Their Setting in the Early Church,” In The Living and Active Word of God: Studies in Honor of Samuel J. Schultz, ed. Morris Inch and Ronald Youngblood (Winona Lake, IN: Eisenbrauns, 1983), 179.