Your original question doesn't list examples; however, in a follow-up post you did cite a few in the comments section. So this post is going to interact (at least in part) with the few examples you listed:
- 1 Cor. 13:2 & Matt. 17:20
- 1 Cor. 13:3 & Matt. 19:21
- 2 Cor. 1:17 & Matt. 5:37
It should be pointed out that some of the references you are making are from the same context. For example, in the first two sets of passages, you cite 1 Cor. 13:2, but then in the second set of passages you cite 1 Cor. 13:3. Since they are drawing from the same Pauline letter (even the very same chapter), I will respond to those two sets of texts succinctly in this way:
You draw a connection between 1 Cor. 13:3 and Matt. 19:21, suggesting that Matthew may be placing Paul’s words onto the lips of Jesus.
But pay attention to Paul's words in 1 Cor. 13:3. The devil is in the details,
καὶ ἐὰν ψωμίσω πάντα τὰ ὑπάρχοντά μου καὶ ἐὰν παραδῶ τὸ σῶμά μου ἵνα
καυθήσομαι ἀγάπην δὲ μὴ ἔχω οὐδὲν ὠφελοῦμαι
And if I give all my possessions to feed the poor, and if I surrender
my body to be burned, but do not have love, it profits me nothing. (1
Cor. 13:3, NASB95)
To the careful reader, the verbal affinities should be quite striking.
The Greek term ὑπάρχοντά (“possessions”) is routinely found in Paul, particularly in contexts where Christ is the prototype (i.e., Phil. 2:6). It is my proposal that rather than Paul being the “prototype” to the Matthean account (Matt. 19:21), it is Christ who is the “prototype” that lays behind the Pauline account (1 Cor. 13:3). Thus, your argument is quite lopsided, backwards even!
τοῦτο φρονεῖτε ἐν ὑμῖν ὃ καὶ ἐν Χριστῷ Ἰησοῦ ὃς ἐν μορφῇ θεοῦ ὑπάρχων οὐχ ἁρπαγμὸν ἡγήσατο τὸ εἶναι ἴσα θεῷ ἀλλὰ ἑαυτὸν ἐκένωσεν μορφὴν δούλου λαβών ἐν ὁμοιώματι ἀνθρώπων
γενόμενος
Have this attitude in yourselves which was also in Christ Jesus,
who, although He existed in the form of God, did not regard equality
with God a thing to be exploited, but emptied Himself, taking the form of a servant, being made in the likeness of men. (Phil.
2:5-7)
In Phil. 2:5, we are called to, “Have this attitude in yourselves which was also in Christ Jesus.” Thus, when Paul pens the words in 1 Cor. 13:3, it is Phil. 2:5-6 that is on his conscience. So impacted by “the Christ-event” (the incarnation), that Paul was moved to imitate Christ in every way. Christ “emptied” Himself of His former glory and riches by “taking the form of a servant, and being made in the likeness of men” (Phil. 2:7),
γινώσκετε γὰρ τὴν χάριν τοῦ κυρίου ἡμῶν Ἰησοῦ Χριστοῦ ὅτι δι᾽ ὑμᾶς
ἐπτώχευσεν πλούσιος ὤν ἵνα ὑμεῖς τῇ ἐκείνου πτωχείᾳ πλουτήσητε
For you know the grace of our Lord Jesus Christ, that though He was
rich, yet for your sake He became poor, so that you through His
poverty might become rich. (2 Cor. 8:9, NASB95)
Not only does Paul allude to Phil. 2:5-6 in 1 Cor. 13:3, but also in 2 Cor. 8:9. All three texts closely correspond. And what's rather interesting, is you actually allude to 2 Cor. in another one of the examples you cited (namely, 2 Cor 1:17), yet missed the connections!
In addition to what I've stated above, Paul was a Jew familiar with his OT (Prov. 28:27, Deut. 15:7-8, Isaiah 58:7), and followed apostolic tradition (Gal. 2:9-10), which was taught by Christ and passed down through the apostles (Lk. 12:33, Lk. 18:18-23, Mk. 10:17-31). Christ's teachings were passed down through tradition, probably being recited on the Lord's day, and most certainly was widely circulated among the Christian community, hence the reason we find it in multiple gospel accounts.
Thus, in every way, Christ is the archetype for Paul.
This provides just one (very good) reason that the first two (sub)sets of texts that you cited do not work. Further, just as a cursory level observation to the first set of texts (1 Cor. 13:2 and Matt. 17:20), it may be that this could be understood as a common Jewish axiom or form of expression, cf. Matt. 17:20, 21:21, Lk. 17:6, Mk. 9:21-23, 11:22-25.