I accept anything you can prove from a KJV, taken in context, including your contention that Luke was not an elder of the 70 chosen in Luke 10. Apostles did have ruling authority. Following is a whole paragraph that I encourage you to read. It deals with apostolic authority and rule. I hope you will pay close attention.
2 Cor10:7 Do ye look on things after the outward appearance? If any man trust to himself that he is Christās, let him of himself think this again, that, as he is Christās, even so are we Christās.
8 For though I should boast somewhat more of our authority, which the Lord hath given us for edification, and not for your destruction, I should not be ashamed:
9 That I may not seem as if I would terrify you by letters.
10 For his letters, say they, are weighty and powerful; but his bodily presence is weak, and his speech contemptible.
11 Let such an one think this, that, such as we are in word by letters when we are absent, such will we be also in deed when we are present.
12 Ā¶ For we dare not make ourselves of the number, or compare ourselves with some that commend themselves: but they measuring themselves by themselves, and comparing themselves among themselves, are not wise.
13 But we will not boast of things without our measure, but according to the measure of the rule which God hath distributed to us, a measure to reach even unto you.
14 For we stretch not ourselves beyond our measure, as though we reached not unto you: for we are come as far as to you also in preaching the gospel of Christ:
15 Not boasting of things without our measure, that is, of other menās labours; but having hope, when your faith is increased, that we shall be enlarged by you according to our rule abundantly,
16 To preach the gospel in the [regions] beyond you, and not to boast in another manās line of things made ready to our hand.
17 But he that glorieth, let him glory in the Lord.
18 For not he that commendeth himself is approved, but whom the Lord commendeth.
Consider this statement about the word of God;
Ro 3:1 What advantage then hath the Jew? or what profit is there of circumcision?
2 Much every way: chiefly, because that unto them (the Jew) were committed the oracles of God.
I think Luke was a Jew.
Pe 5:1Pe 5:1 Ā¶ 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
This is instructions to the elders who were among them, of which Peter includes himself, and who were eye witnesses of the suffering on the cross of Christ. He is not addressing the extent of their ministry but the character of it.
This teaches us that an apostle is an elder but an elder is not necessarily an apostle, unless he is a member of the 12. Remember, this letter is written in an actual historical time frame and must be considered in that context.