Adam Clarke on Acts 8:28

Sitting in his chariot, read Esaias the prophet - He had gone to Jerusalem to worship: he had profited by his religious exercises: and even in travelling, he is improving his time. God sees his simplicity and earnestness, and provides him an instructer, who should lead him into the great truths of the Gospel, which, without such a one, he could not have understood. Many, after having done their duty, as they call it, in attending a place of worship, forget the errand that brought them thither, and spend their time, on their return, rather in idle conversation than in reading or conversing about the word of God. It is no wonder that such should be always learning, and never able to come to the knowledge of the truth.