When Scripture commands us to conduct ourselves in such a manner toward men, as ‘in honor to prefer others to ourselves,’ and faithfully to devote our whole attention to the promotion of their advantage, it gives such commands as our heart can by no means receive without being first cured of our sinful nature.
We are all so blinded and upset by self-love that everyone imagines he has a just right to exalt himself and to under-value all others in comparison to self.
If God has bestowed on us any excellent gift, we imagine it to be our own achievement; and we swell and even burst with pride.
John Calvin, Golden Booklet of the True Christian Life, 2.4.1.