John Calvin Commentary Titus 2:9

"[Exhort] servants to be in subjection to their own masters, [and] to be well-pleasing [to them] in all things; not gainsaying;" — Titus 2:9 (ASV)

Servants, that they be subject to their masters. It has already been said that Paul merely glances at some things by way of example and does not explain these subjects fully, as if he expressly undertook to address them in detail. Accordingly, when he instructs servants to please their masters in all things, this desire to please must be limited to what is appropriate. This is evident from other similar passages where an exception is expressly added, meaning that nothing should be done except according to the will of God.

It should be noted that the Apostle emphasizes primarily this point: those who are under the authority of others should be obedient and submissive. He does this with good reason, for nothing is more contrary to human nature than subjection. There was a danger that they might take the gospel as a pretext for becoming more rebellious, thinking it unreasonable that they should be subject to the authority of unbelievers. Pastors ought, therefore, to exercise all the more care and diligence to subdue or check this rebellious spirit.