Albert Barnes on Acts 8:36

As they went on their way.

A certain water. The expression used here does not determine whether this was a river, a brook, or a pond or 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, whether that was by sprinkling, pouring, or immersion. It must be admitted, I think, that there might have been water enough for either. Grotius says they came "to a fountain which was in the neighbourhood 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, etc. This shows that he had been instructed by Philip in 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, Mt 3:6.

(c) "what doth hinder me" Acts 10:47