This weekend Protestants around the world will celebrate the 500th anniversary of Reformation Sunday, memoration of Martin Luther’s nailing his ninety-five theses to the church door Wittenberg, Germany on October 31, 1517.

As Stephen Nichols says,“when we think of Martin Luther, we think of thesolas, we think of the authority of Scripture, we think of the necessity of justification by faith alone through grace alone in Christ alone. But one of the crucial doctrines of Luther is vocation.”

“For Martin Luther, vocation is nothing less than the locus of the Christian life,” said Gene Edward Veithlast year in an Acton Commentary. “God works in and through vocation, but he does so by calling human beings to work in their vocations.”

God calls every believer to reconciliation with himself. This is the calling to repentance and conversion, and includes our sanctification and obedience, which leads us to serve others. But we also have various other callings that flow from this. As the Apostle Paul says, “each person should live as a believer in whatever situation the Lord has assigned to them, just as God has called them” (1 Corinthians 7:17). The “situation the Lord has assigned” passes the various areas that fall under the rubric of vocation.

Here are five things we should know about vocation:

Vocation is about love and service — ”The purpose of vocation is to love and serve one’s neighbor,” says Veith. “This is the test, the criterion, and the guide for how to live out each and every vocation anyone can be called to: How does my calling serve my neighbor?”

Vocation is the specific way in which God calls us to live as a Christian in the world and serve our neighbor.

Vocation is more than your job — We often use the term vocation in reference to our careers or occupation. But while our jobs are a way—maybe even the most significant way—we serve others, the Biblical concept of vocation is more expansive. It includes all the roles in which we are called to serve and minister to our neighbors.

Vocation is not self-chosen — A vocation is something we are called to by God. It is not something we choose for ourselves. We discover our vocations by considering what resources God has given us for stewardship (i.e., talents, interests, abilities) and the people he has put in our lives (e.g., parents, children).

You have multiple vocations — We are called to serve in various spheres, such as the family, the workplace, church, etc. In each of these we have a vocation—sometimes multiple vocations (e.g., being both a parent of a child and the child of a parent).

The primary vocation of a Christian is to be a Christian — While most of our vocations are equal before God, one stands apart from all others: our calling to be a follower of Christ. This is the most important vocation we will ever have in this life.