What were major critiques of Armstrong's teachings on law observance and Old Testament festivals?

1. A clear break with mainstream Christianity

Armstrong taught that Christians are required to observe Old Testament laws and festivals—Sabbath from Friday sundown to Saturday sundown, Passover, Pentecost, and the Feast of Tabernacles—rather than the Sunday and holiday practices of most churches; this doctrinal stance is central to Armstrongism and is repeatedly noted in reporting on his movement ^{[1] [3]}. Critics see that teaching as a fundamental doctrinal divergence from historic Christian claims about fulfillment in Christ ^[2].

2. The chief theological critique: law vs. grace

Mainstream critics argue Armstrong substituted Old Testament legal observance for the New Testament gospel of grace, contending his emphasis on law and festivals undermines salvation by faith in Christ alone; sources state that opponents describe Armstrongism as replacing “the exchange at the cross” with Mosaic requirements ^[2]. GotQuestions and similar evaluators explicitly frame Armstrong’s insistence on Old Covenant observance as a theological error that conflicts with orthodox Protestant teaching ^[2].

3. Charges of legalism and institutional control

Observers and former insiders describe Armstrong’s system as legalistic: strict tithing rules, mandatory observance of Holy Days, dietary restrictions, and hierarchical enforcement of doctrine formed a behavioral code for members, and splinter groups that preserved Armstrong’s teachings continued those practices—leading critics to call some of these offshoots cult‑like ^{[4] [5]}. Reporting on the Restored Church of God highlights outside organizations labeling its Old‑law emphasis as adding human requirements to salvation ^[4].

4. British Israelism deepens the controversy

Armstrong’s movement often combined law observance with British Israelism—the claim that Western European peoples are descended from the Ten Lost Tribes—which critics say colors his festival theology with ethno‑historical claims and prophecy frameworks that mainstream Christians reject; analysts list British Israelism as a core belief adding doctrinal weight to observance rules ^[3]. That combination intensified alarm among scholars and ex‑members who saw an ideological agenda beyond simple liturgical preference ^[3].

5. Institutional fallout and schisms as evidence of doctrinal strain

After Armstrong’s death and doctrinal shifts in the Worldwide Church of God, many former Armstrongists formed splinter groups expressly to retain Old Testament observance; the proliferation of “one true church” claimants and dozens of offshoots is cited as evidence the teachings produced sustained institutional division and contested authority ^{[5] [6]}. Critics use the persistent fragmentation to argue Armstrong’s model centralized authority and produced dependence on denominational leaders ^[6].

6. Defenders: restoration, biblical literalism, and continuity

Supporters framed Armstrong’s observance of festivals and law as a “restoration” of biblical practice and argued Leviticus 23 feasts are God’s “appointed festivals” for all believers; groups continuing his teachings present Old Testament holy days as the original and therefore authoritative schedule for worship ^{[7] [8]}. United Church of God and allied writers explicitly argue that traditional Christian holidays displaced God’s appointed feasts, offering an affirmative rationale for Armstrong’s calendar ^[8].

7. What sources do and do not say about pastoral outcomes

Available sources document doctrinal disputes, schisms, and external labels such as “cult” applied by critics to some Armstrong offshoots; they describe institutional practices (tithes, feasts, Sabbath observance) and ideological elements (British Israelism) that drive critique ^{[4] [3]}. Available sources do not mention systematic empirical studies showing whether Armstrong’s festival observance produced better or worse spiritual outcomes for adherents—those data are not found in current reporting.

8. Why the debate matters now

The controversy endures because the core dispute—whether Christ fulfilled Torah obligations or left certain Mosaic observances binding—touches central Christian claims about law, grace, and covenant identity; Armstrongism packages that debate with organizational practices (tithes, policing of holidays) and ethnic prophecy (British Israelism), which makes theological disagreement also institutional and social ^{[1] [3] [4]}. Readers should weigh both the definitional claims of Armstrong’s followers and the theological and sociological critiques made by mainstream Christian commentators and watchdogs ^{[2] [4]}.