John Calvin Commentary Acts 4:20

"for we cannot but speak the things which we saw and heard." — Acts 4:20 (ASV)

For we cannot. Many things that are discovered by hearing and seeing may, indeed, ought to be concealed when the question concerns maintaining peace. For this is an act of discourtesy and wicked stubbornness to stir up and cause a commotion about unnecessary matters; but the apostles do not speak generally when they say they cannot but speak.

For the gospel of Christ is now at stake, in which consists both the glory of God and the salvation of men. It is an unfitting thing, and sacrilegious wickedness, that it should be suppressed by human prohibitions and threats; for God commands that his gospel be preached, especially since they knew that they were chosen to be witnesses and preachers of Christ, and that God had opened their mouth.

Therefore, whoever puts them to silence endeavors as much as he is able to abolish the grace of God and destroy the salvation of men. And if a prohibition so wicked stops our mouths, woe to our sluggishness! Now, let all men see what confession God requires of them, lest, when they keep silence because of men, they hear a fearful voice proceed from the mouth of Christ, by which their unfaithfulness shall be condemned.

And as for those who are called to the office of teaching, let them not be terrified by any threats of men, nor by any pretense of authority, but let them execute that office which they know is enjoined upon them by God. Woe to me, says Paul, if I do not preach the gospel, because this responsibility has been committed to me! (1 Corinthians 9:10). We ought not only to set this commandment of God against the tyrannical commandments of men, but also against all hindrances that Satan often thrusts in to interrupt and obstruct the course of the gospel.

For we need a strong shield to ward off such severe assaults, which all the ministers of Christ experience. But however we fare, this is an unyielding defense: that the preaching of the gospel pleases God, and therefore that it can under no circumstances be suppressed.