Ben Witherington writes about the Problem with Evangelical Theology:
What has concerned me as an exegete and NT scholar is that all of the major Evangelical theologies now on offer (Calvinism, Wesleyanism, Dispensationalism, Pentecostalism and sometimes several of these combined) have their exegetical weaknesses– some more glaring than others. What is most interesting to me is the fact that these weaknesses consistently show up when one or another of these theologies try to say something distinctive or different– something that distinguishes them from other Evangelical theologies. For example, the rapture theology of Dispensationalism, the predestinarian/eternal security theology of Calvinism, the charismatic gifts requirement tagged to some experience subsequent to conversion of Pentecostalism, or some forms of the perfection argument in Weslyanism. All of these ‘distinctives’ in fact are ideas that are very weakly grounded in Scripture. Indeed often one or another of these ideas seems to be supported in spite of what Scripture says over and over again.
This is probably a good general rule of thumb for theology: If it’s unique its probably either an error or a heresy. Just keep that in mind.