4:20 For the kingdom of God - Real religion, does not consist in words, but in the power of God ruling the heart.

1 Corinthians 4:20 Parallel Commentaries

Human Characters Determined Only by Divine Decision.
"But with me it is a very small thing that I should be judged of you, or of man's judgment; yea I judge not mine own self. For I know nothing by myself, yet am I not hereby justified: but he that judgeth me is the Lord." Corinth was one of the principal cities of Greece. Enjoying every advantage of situation, it became rich and populous. Most cities in similar circumstances have become vicious. This became exceedingly so. The religion of Corinth was paganism, which naturally led to sundry vices. …
Andrew Lee et al—Sermons on Various Important Subjects

Distinguishing Grace
We shall now for a moment or two endeavor to put down our pride by observing wherein God hath distinguished us and made us to differ, and then by noticing that all this cometh of him, and should be a reason for humiliation, and not for boasting. 1. Many of us differ from others in God's providential dealings towards us. Let us think a moment how many there are of God's precious and dearly beloved children, who at this moment are in the depths of poverty. They are not walking about in sheepskins and …
Charles Haddon Spurgeon—Spurgeon's Sermons Volume 5: 1859

Against Vain and Worldly Knowledge
"My Son, let not the fair and subtle sayings of men move thee. For the kingdom of God is not in word, but in power.(1) Give ear to My words, for they kindle the heart and enlighten the mind, they bring contrition, and they supply manifold consolations. Never read thou the word that thou mayest appear more learned or wise; but study for the mortification of thy sins, for this will be far more profitable for thee than the knowledge of many difficult questions. 2. "When thou hast read and learned many …
Thomas A Kempis—Imitation of Christ