Adam Clarke on Ephesians 3:13

I desire that ye faint not - In those primitive times, when there was much persecution, people were in continual danger of falling away from the faith who were not well grounded in it. This the apostle deprecates, and advances a strong reason why they should be firm: "I suffer my present imprisonment on account of demonstrating your privileges, of which the Jews are envious: I bear my afflictions patiently, knowing that what I have advanced is of God, and thus I give ample proof of the sincerity of my own conviction. The sufferings, therefore, of your apostles are honorable to you and to your cause; and far from being any cause why you should faint, or draw back like cowards, in the day of distress, they should be an additional argument to induce you to persevere."