John Calvin Commentary Acts 8:28

"and he was returning and sitting in his chariot, and was reading the prophet Isaiah." — Acts 8:28 (ASV)

He read Esaias. The reading of the prophet shows that the eunuch did not worship a God thoughtlessly, according to his own understanding or one he had conceived for himself; rather, he worshipped the God whom he knew through the doctrine of the law. And surely this is the right way to worship God: not to grasp at mere and empty rites, but to join the Word to them, otherwise there will be nothing but what is haphazard and confused.

And certainly, the form of worship prescribed in the Law differs in no way from human inventions, except that God gives light there by His Word. Therefore, only those who are God’s students—that is, those who are taught in His school—worship rightly. But a person seems to waste his effort when he reads without profit.

For he confesses that he cannot understand the prophet’s meaning unless he is helped by some other teacher. I answer that, just as he read the prophet with a desire to learn, so he hoped for some fruit, and he indeed found it. Therefore, why does he deny that he can understand the passage he was reading?

He does so because he openly confesses his ignorance in more obscure passages. There are many things in Isaiah that need no lengthy exposition, such as when the prophet preaches about the goodness and power of God, partly to invite men to faith, and partly to exhort and teach them to lead a godly life.

Therefore, no one will be so uninstructed or dull as not to profit somewhat from reading that book, even though he will perhaps scarcely understand every tenth verse.

Such was the eunuch’s reading. For since, according to his capacity, he gathered those things that served for edification, he gained some definite profit from his studies. Nevertheless, though he was ignorant of many things, he did not grow weary, so as to cast away the book.

This is how we also must read the Scriptures. We must eagerly and with a ready mind receive those things that are plain and in which God reveals His mind.

As for those things that are hidden from us, we must pass over them until we receive greater light. And if we do not grow weary with reading, it will in time come to pass that Scripture will become more familiar through continual use.