The term pastor usually refers to an ordained person within a Christian church

The term pastor usually refers to an ordained person within a Christian church. In some countries the term is more usually used in traditional Protestant churches but is also used in reference to priests and bishops within the Roman Catholic, Eastern Orthodox, and Oriental Orthodox churches. The word itself is derived from the Latin word pastor which means shepherd. The term pastor is also related to the role of elder within the New Testament, but is not synonymous with the biblical understanding of minister.

The usage of pastor comes from its use in the Bible. In the Hebrew Bible (or Old Testament) the Hebrew word רעה (raʿah) is used. The word is used 173 times and can describe the feeding of sheep as in Genesis 29:7 or the spiritual feeding of human beings as in Jeremiah 3:15, "And I will give you pastors according to mine heart, which shall feed you with knowledge and understanding" (KJV).

In the New Testament, the Greek noun ποιμήν (poimēn) and verb ποιμαινω (poimaino) are usually translated shepherd or to shepherd. The two words are used a total of 29 times in the New Testament, most frequently referring to Jesus. For example, Jesus called himself the "Good Shepherd" in John 10:11. The same words are used in familiar Christmas story (Luke 2) referring to literal shepherds.

In five New Testament passages though, the words are refer to church workers.

* John 21:16 - Jesus told Peter: "Feed [shepherd] my sheep" (KJV)
* Acts 20:17 - the Apostle Paul summons the elders or presbyters of the church in Ephesus to give a last discourse to them; in the process, in Acts 20:28, he tells them that the Holy Spirit has made them bishops, and that their job is to shepherd the flock of God among them.
* 1 Corinthians 9:7 - Paul says, of himself and the apostles: "Who feedeth [shepherds] a flock, and eateth not of the milk of the flock?" (KJV)
* Ephesians 4:11 - Paul wrote "And He gave some, apostles; and some, prophets; and some, evangelists; and some, pastor(s) and teachers" (KJV)
* 1 Peter 5:1-2 - Peter tells the elders among his readers that they are to, "Feed [shepherd] the flock of God which is among you..." (KJV)

Arguably from the earliest centuries of Christian history, the church had three orders which were considered divinely ordained: bishops, priests and deacons. Each was only considered authoritative and able to administer the sacraments if one had valid apostolic succession (i.e., traceable lineage of ordinations back to the original bishops, the Apostles themselves). However, Protestant communities since the Reformation generally disregard this practice, or dispute the existence of apostolic succession.