Brother David W. Cloud in his Way of Life Encyclopedia[9] explains the term “doctrine” in the context of the whole postmodern worldview. His comments are excerpted below:
DOCTRINE. Doctrine simply means teaching, but the biblical usage refers to sound teaching based on the Word of God. The two Greek words translated "doctrine", didaskalia and didache, are also translated "teacheth" (Ro. 12:7) and "learning" (Ro. 15:4). These words are used more than 140 times in the N.T., which shows how important doctrine is before God. Other terms which refer to doctrine are "truth" (1 Ti. 2:4), "the faith" (1 Ti. 3:9; 2 Ti. 3:8; Tit. 1:13), "wholesome words" (1 Ti. 6:3), and "sound words" (2 Ti. 1:13). Doctrine (and its companion terms) is referred to 59 times in the Pastoral Epistles alone. "The truth" is referred to 10 times in 2 and 3 John alone.