Romans 9:21

Power. Greek exousia, “right,” “authority.” The argument is that to deny that God has the right to do with man as He will is equivalent to denying that the potter has complete control over his clay, which is obviously absurd. Paul may be alluding to Jer. 18:6. It is important to notice that in this declaration in Jeremiah the conditional nature of God’s promises is clearly set forth (Jer. 18:7-10). God is working for the good of men and nations, but they by their stubbornness and perverseness bring ruin upon themselves.

The same lump. From the same lump of clay the potter, at his own discretion, may choose to make one vessel for a noble purpose and another for a humbler use. Similarly, God has authority over all mankind, and will deal with men according to His own benevolent purposes. In working for the salvation of mankind God sees fit to permit men and nations to suffer the consequences of their own rebellion. That which He thus permits is often represented in the Bible as though directly done by Him (see on 2 Chron. 18:18).