Acts 8:29

‘And the Spirit said to Philip, “Go near, and join yourself to this chariot.” '

It was quite normal for solitary travellers to join themselves up with a travelling caravan for safety reasons, and so Philip's approach would neither be resented nor suspected. Others would be walking with the caravan. But Philip knew that God had sent him here for a purpose, and sensing the prompting of the Spirit, he recognised that he had to approach The Man himself. Thus he attached himself to his conveyance and ran alongside.