Important, but not of foremost importance

Tim Challies offers what he calls "A Theological Toolbox," the ways he uses most often to approach the questions "What is of primary importance?" and "How can I know God's will?" His responses to the first question are informed by Mohler's "theological triage" summarized here:

First-level doctrines are those that are those that are most central and essential to the Christian faith. They are doctrines such as the Trinity, the full deity and humanity of Jesus Christ, justification by faith, and the authority of Scripture. These are the doctrines that demanded councils and creeds. These are the doctrines that if you deny, you will soon deny the Christian faith altogether.

Second-level doctrines are significant issues, but ones for which there is still disagreement among gospel-believing Christians. We can still affirm the faith of those who believe the opposite of what we believe, but we may not be able to enjoy denominational or local-church fellowship with them. These are issues such as the meaning and mode of baptism, and whether or not women are permitted to serve as pastors.

Third-level doctrines are those for which Christians may disagree, even while maintaining the closest kind of fellowship. You and I may believe different things here, but it will not diminish our fellowship and we can easily participate in the same local church. Eschatology is an example of this kind of doctrine, where as long as we affirm the bodily and victorious return of Jesus Christ, we may disagree on exactly what sequence of events will lead to it.

Theological triage sorts doctrines into one of these three categories and helps us see which issues are the most urgent and important and which issues ought to receive the most thorough and vigorous defense. This is a tool I find myself pulling out of my toolbox again and again. ....

My denomination affirms a belief about the Sabbath that differs from that of most Christians. We are convinced that it remains, and should be celebrated, on the seventh day of the week rather than on Sunday. But that conviction is not what Mohler (and Challies) would categorize as a "first-level doctrine." It is rather "second level." I have found this way of thinking about doctrine very helpful.

Challies' response to the second question is equally helpful

A Theological Toolbox | Challies Dot Com