The New Testament was originally written in Greek. The passages of scripture below use the following Greek words together:
Elder – Greek word – presbuteros – literally means: old man, aged; an elder.
Overseers – Greek – episkopos – epi means over and skopos means to look or watch, therefore, one who watches over, a superintendant. Note that this Greek word episkopos, has been translated as bishop in 1 Timothy 3v1-2.
Feed – Greek – poimaino – means to feed, shepherd, to pastor.
17 And from Miletus he sent to Ephesus, and called the elders of the church. …
28 Take heed therefore unto yourselves, and to all the flock, over the which the Holy Ghost hath made you overseers, to feed the church of God, which he hath purchased with his own blood.
In Acts 20v17 & 28 above, Paul, the apostle, instructs the elders (presbuteros – elder), who have been made overseers (episkopos – overseer), to feed (poimaino – pastor, shepherd, feed) the Church of God.
Peter, the apostle, uses the same words in the same way, in the scripture below:
1 Peter 5v1
The elders which are among you I exhort, who am also an elder, and a witness of the sufferings of Christ, and also a partaker of the glory that shall be revealed: 2 Feed the flock of God which is among you, taking the oversight thereof, not by constraint, but willingly; not for filthy lucre, but of a ready mind; 3 Neither as being lords over God’s heritage, but being ensamples to the flock. 4 And when the chief Shepherd shall appear, ye shall receive a crown of glory that fadeth not away.
Again, this scripture shows us that the elder is to take the oversight (as an overseer) and to feed (pastor) the flock of God (which is the Church).
So we see that an elder, pastor and overseer are one and the same thing.