Please provide Scriptual reference to where Peter describes Paul as one of the “Twelve”
DCNBILL,
Please see the following passages:
1 Peter 1:1 Peter, an apostle of Jesus Christ, to the strangers scattered throughout Pontus, Galatia, Cappadocia, Asia, and Bithynia,…
2 Peter 1:1 Simon Peter, a servant and an apostle of Jesus Christ, to them that have obtained like precious faith with us through the righteousness of God and our Saviour Jesus Christ:
2 Peter 3:2 That ye may be mindful of the words which were spoken before by the holy prophets, and of the commandment of us the apostles of the Lord and Saviour:
2 Peter 3:13 Nevertheless we, according to his promise, look for new heavens and a new earth, wherein dwelleth righteousness.
14 Wherefore, beloved, seeing that ye look for such things, be diligent that ye may be found of him in peace, without spot, and blameless.
15 And account that the longsuffering of our Lord is salvation; even as our beloved brother Paul also according to the wisdom given unto him hath written unto you;
16 As also in all his epistles, speaking in them of these things; in which are some things hard to be understood, which they that are unlearned and unstable wrest, as they do also the other scriptures, unto their own destruction.
17 Ye therefore, beloved, seeing ye know these things before, beware lest ye also, being led away with the error of the wicked, fall from your own stedfastness.
18 But grow in grace, and in the knowledge of our Lord and Saviour Jesus Christ.
1 Timothy 1:1 Paul, an apostle of Jesus Christ by the commandment of God our Saviour, and Lord Jesus Christ, which is our hope;
2 Timothy 1:1 Paul, an apostle of Jesus Christ by the will of God, according to the promise of life which is in Christ Jesus,
…
9 Who hath saved us, and called us with an holy calling, not according to our works, but according to his own purpose and grace, which was given us in Christ Jesus before the world began,
10 But is now made manifest by the appearing of our Saviour Jesus Christ, who hath abolished death, and hath brought life and immortality to light through the gospel:
11 Whereunto I am appointed a preacher, and an apostle, and a teacher of the Gentiles.
Titus 1:1 Paul, a servant of God, and an apostle of Jesus Christ, according to the faith of God’s elect, and the acknowledging of the truth which is after godliness;
Ephesians 1:1 Paul, an apostle of Jesus Christ by the will of God, to the saints which are at Ephesus, and to the faithful in Christ Jesus:
Galatians 1:1 Paul, an apostle, (not of men, neither by man, but by Jesus Christ, and God the Father, who raised him from the dead

2 And all the brethren which are with me, unto the churches of Galatia:
2 Corinthians 1:1 Paul, an apostle of Jesus Christ by the will of God, and Timothy our brother, unto the church of God which is at Corinth, with all the saints which are in all Achaia:
1 Corinthians 1:1 Paul, called to be an apostle of Jesus Christ through the will of God, and Sosthenes our brother,
2 Unto the church of God which is at Corinth, to them that are sanctified in Christ Jesus, called to be saints,
Romans 1: 1 Paul, a servant of Jesus Christ, called to be an apostle, separated unto the gospel of God,
2 (Which he had promised afore by his prophets in the holy scriptures,)
3 Concerning his Son Jesus Christ our Lord, which was made of the seed of David according to the flesh;
4 And declared to be the Son of God with power, according to the spirit of holiness, by the resurrection from the dead:
5 By whom we have received grace and apostleship, for obedience to the faith among all nations, for his name:
6 Among whom are ye also the called of Jesus Christ:
7 To all that be in Rome, beloved of God, called to be saints:
Peter and Paul use the same introduction patterns, and Peter refers to Paul’s “epistles” as though they are “scripture” although he says they are sometimes “hard to be understood”. He does not differentiate that his own personal use of the word “apostle” to describe his own calling is any different than the introductions Paul used in his epistles. They both consider themselves “called of God, and not of men” with a calling that is specific–that of being an “apostle”.
Have a good day. It appears that Peter and Paul were good friends, and respected each other greatly.