10 not pilfering, but showing all good fidelity, that they may adorn the doctrine of God our Savior in all things.
but [emphatic] showing all good fidelity [dependability],
“Showing” means to show for the purpose of proving something. There should be no doubt about the loyalty of an employee to an employer. Slaves were to demonstrate that they could be fully trusted. They were to be loyal and trustworthy towards their masters.
“Good” here refers to intrinsic good, not apparent good. The good of the slaves was to go beyond the appearance of good to doing what was best for the masters, regardless of who or what they were.
Christianity addresses social structures by the gospel and the changed lives of believers.
An employee is to be trustworthy and reliable. The employer can count on this person to be dependable to do his job.
The Bible does not try to change social structures in themselves. The issue for it is how Christians behave in an orderly manner. God does not advocate revolt against social structures. The believer is to do the opposite—to please those higher in the social order.
There is a difference between social respectability and Christianity respectability. The difference rests in purpose. Respect for authority in the social structure will gain the appreciation of the lost.