Although words like cult, sect, faction, and division appear in both the Old and New Testaments (e.g. Acts 24:5; Acts 24:14; Gal 5:20; Tit 3:10; 2 Pet 2:1), the word "orthodoxy" cannot be found in the Bible. Few people would disagree, however, with the idea that there must be a standard that judges orthodoxy from heresy; a way to determine whether a particular group is orthodox or a cult.
Orthodoxy and heresy originated with God and Satan, respectively. God is self-existent (Exo 3:14) and the creator of heaven and earth (Gen 1:1). Satan, on the other hand, is a created being (Rev 12:9; Rev 20:2), who appears as the serpent in Gen 3:1.