Belief does not necessarily determine behavior, at least according to Scripture1,2,3,4,5,6,7,8,9. In particular, we have Jesus’ statement1 to those who Scripture confirms had believed! These disciples were only “truly” disciples if they continued in the gospel word and did works in accordance with the will of the Father7. Paul effectively says the same thing to the Corinthians6 – he literally says their belief could be in vain. Likewise, Peter says the same thing to the scattered Christians8. All three of these explicit statements fly directly in the face of an absolute statement that “belief determines behavior.”
Good works5/obedience3,8 (e.g. “behavior”) should follow belief/faith and indeed must if one’s faith is to be effective1,5,6,9. However, as Jesus demonstrates2 and James plainly states5, even demons believe (and obivously don’t “live for Jesus” as Pastor Morris puts it). Jesus1, Paul4,6 and Peter8 confirm this hopeful but not automatic relationship between belief and behavior, and Paul shares his own struggle with this – a constant battle in the flesh4.