As they went on their way - In their journey.
A certain water - The expression used here does not determine whether this was a river, a brook, or a standing pool. And there are no circumstances to determine that. It is well known, however, that there is no large river or very considerable stream in this vicinity. All that is intimated is that there was water enough to perform the rite of baptism. Grotius says they came “to a fountain which was in the neighborhood of Bethsora, in the tribe of Juda, at the twentieth milestone from Aelia (Jerusalem) to Hebron.” This is, however, a tradition taken from Eusebius. The place is still shown (Pococke).
What doth hinder me ... - This shows that he had been instructed by Philip on the nature and design of baptism. It evinces also a purpose at once to give himself to Christ, to profess his name, and to be dedicated to his service.
To be baptized - On the meaning of the word “baptize” βαπτίζω baptizō, see all the notes on Matthew 3:6, Matthew 3:16.