The Spirit had enjoined Philip to proceed to that road: the eunuch himself, too, was not found idle, nor as one who was suddenly seized with an eager desire to be baptized; but, after going up to the temple for prayer's sake, being intently engaged on the divine Scripture, was thus suitably discovered-to whom God had, unasked, sent an apostle, which one, again, the Spirit bade adjoin himself to the chamberlain's chariot. The Scripture which he was reading falls in opportunely with his faith: Philip, being requested, is taken to sit beside him; the Lord is pointed out; faith lingers not; water needs no waiting for; the work is completed, and the apostle snatched away.
Consider, I ask you, what a great effort it was not to neglect reading even while on a journey, and especially while seated in a chariot. Let this be heeded by those people who do not even deign to do it at home but rather think reading the Scriptures is a waste of time, claiming as an excuse their living with a wife, conscription in military service, caring for children, attending to domestics and looking after other concerns, they do not think it necessary for them to show any interest in reading the holy Scriptures.
Great also is his studiousness, that even sitting in his chariot he read. Was reading the prophet Esaias. For the road was desert, and there was no display in the matter. Observe also at what time: in the most violent heat of the day.
[AD 220] Tertullian on Acts 8:28