Paul may quote Luke (10:7)
And in the same house remain, eating and drinking such things as they give: for the labourer is worthy of his hire. Go not from house to house.
in
1 Timothy 5:18
For the scripture saith, "thou shalt not muzzle the ox that treadeth out the corn." And, "The labourer is worthy of his reward."
"The labourer is worthy of his reward." is not found in the Old Testament. 1 Timothy is one of the disputed letters by Paul. Some letters by Paul are thought to be authentically written or dictated by Paul
while others are thought to be Pseudepigrapha - i.e they are disputed. Some believe that Paul preferred to confront his Jewish educated critics by quoting from the Septuagint, indicating
that Paul would have less of a tendency to quote Gospel accounts.
Gospel of Luke Chapter 10 - NIV English Translation - Embedded
1 Timothy Chapter 5- NIV English Translation - Embedded