Not exactly a righteous stand against the sin of slavery. But Paul's frame of reference should be taken into account. He was of the faith expectation, as have every generation of believers, that Christ would return and the rapture would ensue, post haste, in his lifetime. Paul, thus, did not see himself as a social critic, but rather, as an evangelist preparing both slaves and masters for the imminant return of Christ. . now back to Terry and Phil. . sorry!
The bible was not written in English. Master here does not mean a slave master. It means employer, etc.