The best way to determine whether a doctrine is truly biblical is to find whether it is explicitly taught in the Bible. Any particular belief can either be biblical, biblically-based, extra-biblical (not mentioned in the Bible), or unbiblical (against the teachings of the Bible).
How do we know if a doctrine is really biblical?
A biblical doctrine can be clearly discovered in the Bible itself. For example, the fundamental belief of Jesus being resurrected from the dead is affirmed in Scripture: "For I delivered to you as of first importance what I also received: that Christ died for our sins in accordance with the Scriptures, that he was buried, that he was raised on the third day in accordance with the Scriptures" (1 Corinthians 15:3-4). The Bible predicted this event and then recorded the resurrection in each of the four Gospel accounts. Virtually every New Testament book speaks about the resurrection either directly or indirectly.
Other doctrines can be biblically-based or based on biblical principles but may not be explicitly taught in the Bible. For example, the Bible teaches that helping the poor is a Christian responsibility. The way in which a Christian helps, however, can vary greatly. Both child sponsorship and microfinance help the poor. Giving directly through your church and helping other organizations helps the poor. There can be a variety of biblically-based applications based on the biblical doctrine of kindness to the poor.
A third category of doctrines can be considered extra-biblical. This means that the teaching is not found in the Bible, but is also not against the Bible. For example, a person may believe God has led her to be a nurse. There is nothing wrong with this vocation. In fact, it is very noble and helpful. Yet the command to become a nurse is not in the Bible. Another example is the concept of voting in democratic elections. The idea of government by the people and for the people sounds beneficial, but is not explicitly taught in Scripture.
A fourth category of doctrines can be considered unbiblical. By unbiblical, the idea is that it is against the clear teachings of the Bible. A person who wants to have an affair will find no doctrine in Scripture to justify this activity. Instead, this person will find clear commands against extramarital relationships. For example, Hebrews 13:4 is clear, "Let marriage be held in honor among all, and let the marriage bed be undefiled, for God will judge the sexually immoral and adulterous."
Complications and problems arise when people confuse these categories. For example, some people would suggest that whether Jesus sinned or not is a matter of preference (extra-biblical) rather than a biblical doctrine. To do so contradicts the clear teaching of Scripture (Hebrews 4:15). At other times, people can become like the Pharisees and make traditions equal to or greater than the commands of God (Mark 7:7).
Our desire as Christians should be to stand firm where Scripture stands firm and to allow freedom in areas where Scripture does not give clear commands. We can stand in unity on areas of agreement and allow diversity in areas of non-essentials.
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