Good vs. bad hermeneutic rules: clear passages on an issue vs. passages about different issues

Good hermeneutic rule: clear passages help us with unclear passages on the same issue. Bad hermeneutic rule: a passage about one thing tells us how to interpret passages about a completely different issue. The egalitarian use of Galatians 3:28 as a silver bullet is the bad rule — it takes a passage about salvation and sonship and uses it to control interpretation of passages about church roles and marriage.