John Gill emphasizes that believers should expect to be viewed as strange by the world due to their transformed lives in Christ. He explains that the drastic change in their behavior will lead to misunderstanding and hostility from those who indulge in worldly excesses. Gill encourages the saints not to be discouraged by this opposition, as it stems from the contrast between their righteous living and the sinful practices of others. He highlights the importance of standing firm in faith despite being slandered or criticized for their beliefs and lifestyle.