A “sheepfold” (v.1) was a pen for the sheep made of sticks or stones with an opening for a door. If a man climbed over the wall to get to the sheep, you knew he was a thief. If he went through the door, you knew he was the shepherd.
The sheep in this parable represent Israel (Mt.15:24), and the sheepfold would be the wall the Lord put around Israel, the law (Eph.2:14, 15). The shepherd was the Lord (John 10:11) and the thieves were the false Christ’s that came before the Lord, men like Theudas (Acts 5:36). The “door” was the only way through the wall, and the only way through the Law was to be perfect (James 2:10,11). All the false Christs before the Lord couldn’t meet that standard, and so had to climb over the wall to get to the sheep.
But when the Lord showed up at the wall of the Law, the “porter” let Him in. Porters are men in charge of a door, and in Scripture the doorkeepers guarded the gates of the temple (IIChron.8:12-14) to prevent unclean men from entering (23:19). They would use the Law of course to determine who was clean and who was unclean (Lev.5:2, 13:44, etc.) So the porter here in John 10 represents the Law that examined the Lord and let Him approach the sheep, because He was of course clean in every way.
Then the sheep heard His voice (John 10:3). Didn’t everyone? Not the disobedient (Ezek.12:2) No wonder the Lord said what He said in Mt.11:15! Of course, it is God who allows men to hear (Deut.29:4), not just elect men, as Calvinism teaches, but men who hear the Word (John 18:37 cf. 6:45). The Lord calls the sheep by name (John 10:3), i.e., by the names of the sons of Israel (Ex.28:9-12 cf. Isa. 43:1), believing Israel (Rom.2:28), whom He will someday give a new name (Rev.3:12) when He marries Israel (Rev. 19:7). His name in that day will be “the Lord our right-eousness” (Jer.23:5,6), a name He’ll give to Israel (33:16).
The Lord leads the sheep out of the sheepfold (John 10:3), i.e., out from under the Old Covenant of the Law into the New Covenant (Mt.26:28). Then He “putteth forth His own sheep” (John 10:4) from the rest of apostate Israel (cf. Ex.33:7, Acts 2:40, Heb.13:13).
The sheep know the Lord’s voice (John 10:4) because they study His Word. They don’t know strangers voices (10:5) because they don’t study their words, unlike Christians today who insist on studying false religions and cults.
When the Pharisees (9:40,41) didn’t understand this parable (10:6), the Lord explained that while the door of the sheepfold was the Law, He was the door of the sheep (10:7). You see, it’s not enough to get out the door of the Law, you must go through the door of Christ to be saved (Rev.3:7,8). The key to this door is knowledge (Luke 11:52), for knowing Christ saves us (John 17:3). Most people think they have to climb over high walls to be saved, but it’s not. How hard is it to walk through a door? Of course, you do have to notice that the Lord didn’t say that He was just one of many doors. Noah’s ark only had one door, as did the tabernacle. If you wanted to be saved in those days there was only one door, as is the case today.
Once saved, a Jew was no longer locked up under the law (Acts 15:10) and could “go in and out” (John 10:9). We see this pictured when the Jews that escaped Babylon rebuilt Jerusalem and the only gate that didn’t have locks and bars was the sheep gate (Neh.3:1-15), something that pictured the freedom they’ll have in the “pasture” (John 10:9) of the kingdom of heaven on earth.
Up until now the Lord talked about thieves and robbers plural in the past tense. He now warned about one “thief” to come (10:10), the Antichrist, who is described as a shepherd who receives a deadly wound (Zech.11:17 cf. Rev.13:1,2). He will steal the hearts of the Jews by pretending to care for the sheep, as typified in II Samuel 15:1-6. The Lord didn’t come to steal, but to give “abundant” life (John 10:10) in the kingdom (IIPe.1:11).
A good shepherd gives his life for the sheep (John 10:11), a great shepherd rises again (Heb.13:20), and a chief shepherd returns to show who’s boss (IPet.5:4cf.ITim.6:15)