"Then the Spirit said to Philip, 'Go up and join this chariot.' Philip ran up and heard him reading Isaiah the prophet, and said, 'Do you understand what you are reading?' And he said, 'Well, how could I, unless someone guides me?' And he invited Philip to come up and sit with him."
Philip had a divine appointment with the Ethiopian eunuch. The Holy Spirit had arranged it by first opening up the Ethiopian's heart and mind to scripture. Then, at the moment he was fully prepared to receive Christ, the Spirit moved Philip to go to the Ethiopian and explain the scripture to him. The result was the evangelization of the Ethiopian. The Spirit is still moving in the hearts and minds of people today, prompting them to seek God. And He is still prompting believers to be His witnesses to those He has prepared. It's up to us to be sensitive to His call and obey. Just as Philip did.