Another example of an exponential improvement in conscience I just thought of is slavery. In olden days, slavery was deemed acceptable, but rarely do you find that to be the case since the 19th century.

Slavery was widespread throughout the Roman Empire. In these early days, Christians did not have the political power to change the slavery system. Paul didn't condemn or condone slavery, but he worked to transform relationships. The Good News begins to change social structures by changing the people within those structures.

" 15 Perhaps you could think of it this way: Onesimus ran away for a little while so you could have him back forever. 16 He is no longer just a slave; he is a beloved brother, especially to me. Now he will mean much more to you, both as a slave and as a brother in the Lord." (Phil. 15,16).

Onesimus was a slave of Philemon and he had run away, but Paul reconciled them back together because he led them both to Christ.

"20 You should continue on as you were when God called you. 21 Are you a slave? Don't let that worry you-but if you get a chance to be free, take it. 22 And remember, if you were a slave when the Lord called you, the Lord has now set you free from the awful power of sin. And if you were free when the Lord called you, you are now a slave of Christ. 23 God purchased you at a high price. Don't be enslaved by the world. [fn3] 24 So, dear brothers and sisters, [fn4] whatever situation you were in when you became a believer, stay there in your new relationship with God" (1 Cor. 7.20-24).

Even though there were slaves in ancient times, they could still be brothers in Christ.

"5 Slaves, obey your earthly masters with deep respect and fear. Serve them sincerely as you would serve Christ. 6 Work hard, but not just to please your masters when they are watching. As slaves of Christ, do the will of God with all your heart. 7 Work with enthusiasm, as though you were working for the Lord rather than for people. 8 Remember that the Lord will reward each one of us for the good we do, whether we are slaves or free.
9 And in the same way, you masters must treat your slaves right. Don't threaten them; remember, you both have the same Master in heaven, and he has no favorites" (Eph. 6.5-9).

"22 You slaves must obey your earthly masters in everything you do. Try to please them all the time, not just when they are watching you. Obey them willingly because of your reverent fear of the Lord. 23 Work hard and cheerfully at whatever you do, as though you were working for the Lord rather than for people. 24 Remember that the Lord will give you an inheritance as your reward, and the Master you are serving is Christ. 25 But if you do what is wrong, you will be paid back for the wrong you have done. For God has no favorites who can get away with evil.
You slave owners must be just and fair to your slaves. Remember that you also have a Master-in heaven" (Col. 3.22-4.1).