So can you please explain the meaning of Eph 4:5?
I believe it is saying that there is only one Lord, only one true Church, and only one valid baptism. As early as the end of the first century, there were numerous different sects of Christianity. Today, as we both know, there are tens of thousands of competing denominations. That is definitely not what the Savior wanted when He established His Church, but it is what has happened.
Can you also explain what Jesus meant in John 17:21 when He, speaking of His church, stated: "that they all may be one, as You, Father, are in Me, and I in You; that they also may be one in Us, that the world may believe that You sent Me."
Sure. I think He was saying that He wanted His followers to have the same perfect unity of will and purpose that He and His Father have.
Jesus was simply using a figure of speech to illustrate his church will never see the grave. In others words, never die.
I agree that He was using a figure of speech. I disagree with how you are interpreting it.
Christ's Apostles, particularly Paul, repeatedly spoke of an Apostasy or "falling away" from the truth that was starting to take place even in his day. Among his statements to Christ's followers, are these:
Acts 20:29 For I know this, that after my departing shall grievous wolves enter in among you, not sparing the flock.
2 Thessalonians 2:3 Let no man deceive you by any means: for that day shall not come, except there come a falling away first, and that man of sin be revealed, the son of perdition…
Galatians 1:6 I marvel that ye are so soon removed from him that called you into the grace of Christ unto another gospel…
2 Timothy 4:3 For the time will come when they will not endure sound doctrine; but after their own lusts shall they heap to themselves teachers, having itching ears…
Paul made it absolutely clear that (1)the flock would not only be attacked,
it would not be spared, (2) Christ would not return to the earth until this universal "falling away" or "apostasy" had taken place, (3) these things were already beginning to take place as he spoke, and (4) the doctrines taught by the Savior would, in time, cease to endure.
So His true church or group of followers have to exist somewhere on this planet.
I believe they are, but it was not because a universal apostasy never took place. It was because the Church Jesus Christ established has been re-established. Paul also prophesied of this.
Scholars beg to differ:
Matthew Henry's commentary of Mat 16:18:
"Christ here promises to preserve and secure his church, when it is built; The gates of hell shall not prevail against it; neither against this truth, nor against the church which is built upon it."
Jamieson Faussett and Brown's commentary:
“of Hades,” or, the unseen world; meaning, the gates of Death: in other words, “It shall never perish.” Some explain it of “the assaults of the powers of darkness”; but though that expresses a glorious truth, probably the former is the sense here."
What you're really saying is that
your scholars beg to differ. No one wants to have to acknowledge that the Church fell into apostasy and that the authority held by Christ's Apostles was lost from the earth. Unfortunately, that's exactly what happened.
I'll get to the rest of your post later today, since I have to quit posting now. I'll just comment on your last statement, since it left me momentarily speechless:
How plain is the truth of God!
It appears to be so plain that 33,000+ different denominations cannot agree on what it is!