How Many Times Does Paul's Epistles Uniquely Quote Jesus?
The answer is zero times except maybe once if you assume the word "Lord" meant Jesus in 2 Cor. 12:7. Christian scholars say we cannot accept that possibility, as we shall see. Otherwise, Paul repeats once, and maybe three times the words of Jesus found in either Luke or John. That's the sum total of the quotes of Jesus in Paul's epistles. Hence, nothing appears in Paul's epistles that represents a unique statement from Jesus either by revelation or that is not present in the gospels.
Paul's Mention of the "Lord" Refusing to Remove A Torment from an Angel of Satan.
Paul in his epistles never says specifically "Jesus" told or revealed something to him. Paul refers once to the "Lord" refusing to release him from a demonic "Angel of Satan" (2 Cor. 12:7), with this "Lord" supposedly explaining the reason was that "my grace is sufficient for thee."
Paul does not differentiate this "Lord" from Yahweh who is equally called Lord--Kyrios- as many as 7000 times in the final Septuagint Greek version of the Original Testament.
It is hard to believe Paul meant the true Lord Jesus spoke this refusal, because how could the true Jesus leave Paul subject to an "Angel of Satan"? Christian scholars acknowledge this dilemma if we attribute this quote to Jesus: This verse can be read so "his [i.e., Paul's] apostolic mission [is cast] under suspicion." (C. Fred Dickason, Demon Possession and the Christian (Crossway, 1989) at 120.) Likewise, David Barr relates that "12:7 is notoriously difficult, prompting Barrett to write 'it can hardly be in the form Paul intended it...." (David L. Barr, The Reality of the Apocalypse(Society of Biblical Lit, 2006) at 105.)
Hence, this single solitary quote in Paul's epistles of possibly Jesus speaking to Paul is denied by Paul-aficionados as truly spoken by our Lord Jesus. This is because it attributes to our Jesus the desire to leave Paul subject to a demonic influence -- what Paul calls an "Angel of Satan." As a result, once this is eliminated for this very good reason, one can affirm that Paul never quotes the true Lord Jesus in Paul's epistles as giving Paul a specific revelation by a vision, trance or an appearance.
Quotes by Paul of Jesus from the Gospels.
Otherwise, Jesus is at most quoted twice or three times by Paul in his epistles from the Gospels. None of these quotes are unique and not found in our canonical gospels.
First, clearly, in 1 Corinthians Paul quotes Jesus from the last supper, using Luke's version. Although it is clearly a quote of Jesus, it is certainly not unique. For more on this, see NOTE at end. Hence, if we exclude Paul from canon, we don't lose these words of the Lord Jesus. They are in Luke's Gospel.
Second, Paul in 1 Corinthians 8:6 says "for us, there is but one God, the Father, from whom all things came and one Lord Jesus Christ," and this is very close to Jesus' prayer to the "Father" in John 17:3, "And this is life eternal, that they might know thee the only true God, and Jesus Christ, whom thou hast sent." If we exclude Paul from canon, we do not lose 1 Corinthians 8:6 because it, or a very similar statement, is already in John 17:3.
A third possible quotation of Jesus by Paul in his epistles is mentioned in Scott Schifferd's FORMATION OF THE NEW TESTAMENT SCRIPTURES blog. It says "Paul quoted Luke 10:7 as 'Scripture' in 1 Timothy 5:18." He adds: "Look again to 1 Timothy 5:18 to see that the 'Scripture' of 1 Timothy 5:18 referred to both Deuteronomy 25:4 and Luke 10:7." (July 29, 2015)
Let's look at 1 Timothy 5:18. Here's the NIV:
For Scripture says, "Do not muzzle an ox while it is treading out the grain," and "The worker deserves his wages." (1 Tim. 5:18, NIV.)
The first quote is clearly from Deuteronomy 25:4 -- "Do not muzzle an ox while it is treading out the grain."
The second does appear to be from Luke 10:7 which reads: "Stay there, eating and drinking whatever they give you, for the worker deserves his wages. Do not move around from house to house." In Greek the words "for the worker deserves his wages" is ho ergates tou misthou. These are almost the identical words in 1 Timothy 5:18.
It could also be a paraphrase from the law rather than a quote from Jesus, as Paul does not refer to Jesus as the source.
"'Do not defraud or rob your neighbor. "'Do not hold back the wages of a hired worker overnight.
Do not take advantage of a hired worker who is poor and needy, whether that worker is a fellow Israelite or a foreigner residing in one of your towns.
Pay them their wages each day before sunset, because they are poor and are counting on it. Otherwise they may cry to the LORD against you, and you will be guilty of sin. [From Cross-references to 1 Tim. 5:18.]
If you simply read the Law, you would conclude the "worker deserves his wages." Hence, Paul's reference is not clearly from Jesus' words in Luke. Even so, this quote -- even if from Jesus' words -- is not unique to Paul's epistles. If we excluded Paul from Holy Scripture, we would not lose these words as they already exist in Luke, and the same thought is in Leviticus and Deuteronomy. We would lose nothing uniquely specifically quoting Jesus if we excluded Paul's epistles from canon.
In Paul's epistles, Paul quotes a "Lord" in a personal revelation refusing to release Paul from an "Angel of Satan," who explains to Paul "my grace is sufficient for thee." (See 2 Cor. 12:7-9.) Scholars hesitate to attribute this horrible attribution to our Lord Jesus. Hence, if this is not counted as a statement by Jesus, Paul not once in his epistles quotes Jesus giving Paul a revelatory statement, whether in a trance, vision or other revelation.
Other than that possibility, Paul only quotes Jesus from the Gospels only once directly -- the communion liturgy (in 1 Cor. 11:24 taken from Luke 22:19) and possibly twice indirectly --(1) in the "worker is worthy of his wages" (in 1 Tim. 5:18 which is either from Luke 10:7 or from Deuteronomy / Leviticus) and (2) in Paul saying "one God, the Father" in 1 Cor. 8:6 which is very close to the "Father...the only true God" in John 17:3.
Paul's Revelations from "Jesus" in Acts
If we expand our scope beyond Paul's Epistles, and we examine also the revelations to Paul in Acts by one claiming "I am Jesus," one notices three more revelations from "Jesus." However, these there revelation-statements still do not involve any message to Christians. They are brief, abrupt, and have no religious or spiritual message to anyone beyond Paul. See our article Paul Never Acts Out A Messenger Role for Jesus.
Communion Liturgy from Luke in Paul's Epistle When A Variant Fixes Error in King James
Jesus in the Last Communion in Matthew 26:26-27 said:
while they were eating, Jesus took bread, and when he had given thanks, he broke it and gave it to his disciples, saying, “Take and eat; this is my body.”
Luke fills in a little more detail:
19 And he took bread, gave thanks and broke it, and gave it to them, saying, “This is my body given for you; do this in remembrance of me.” (Luke 22:19.)
John makes a relevant comment at this point. As we all know, the Psalmist prophesied not one bone of Jesus' would be broken, which the Gospel of John mentions was fulfilled when the soldiers decided not to break Jesus' legs. See John 19:36 ("These things happened so that the scripture would be fulfilled: "Not one of his bones will be broken,")
However, in one version of Paul's epistle to the Corinthians, it would appear Paul misquotes both Luke and Matthew, and says Jesus' body was "broken" for the apostles. In 1 Cor. 11:24, Paul in the King James quotes Jesus saying "this is my body broken for you." (KJV, Aramaic, King James 2000, American King James, Websters, Weymouth, World English, Young's Literal).
However, Jesus did not say, and could not possibly have said, as John 19:36 confirms, what Paul per the KJV attributes to Jesus: "This is my body broken for you."
So is this Paul's fault, or a transmission problem?
Many translations do not have "broken" unlike the KJV. See Biblios 1 Cor. 11:24. So the following translations only say Paul quotes the liturgy as "my body is for you" -- NIV, NLT, ESV, NASB, ISV, God's Word, Darby. There are some legitimate variants of 1 Cor. 11:24 that support this: see this list. It explains:
TEXT: "This is my body which is for plyou."
EVIDENCE: p46 S* A B C* 33 1739*
TRANSLATIONS: ASV RSV NASV NIV NEB TEV
For example P 46 means Papyrus 46. This papyrus indeed has coverage of 1 Cor. 11. And it dates from 175-225 AD. ("Papyrus 46," Wikipedia.) The S* is the oldest complete NT from 340 AD - the Sinaiticus. This gives substantial support for a transmission error, rather than an error by Paul.
Let's compare this with the sources for "broken" for you:
NOTES: "This is my body which is broken for plyou."
EVIDENCE: Sc C3 Db,c G K P Psi 81 104 614 630 1241 1739 margin 1881 2495 Byz Lect three lat syr(p,h)
TRANSLATIONS: KJV ASVn RSVn NASVn
The keys to abbreviations such as this are at this site. The Sc is a "corrector" of the Sinaiticus, so it comes later than the earlier Sinaiticus upon which the variant above in part relies. The C3 is Ephraemi Rescriptus from the 5th Century. Psi and all numbered manuscripts are from 5th Century forward. Thus, Papyrus 46 must be deemed the best and most original, confirmed by the Sinaiticus prior to the corrector version.
So Paul is not guilty of a contradiction here. It is a transmission error.