And he commanded the chariot to stand still: and they went down both into the water, both Philip and the eunuch; and he baptized him.

People's New Testament

8:38 They both went down into the water. Abbott states:

The original undoubtedly implies a going, not to, but into, the water.''

And Ripley says:

No sufficient reason can be given why the parties went down into the water, but for the sake of the immersion of the new convert.''

Wesley's Notes

8:38 And they both went down - Out of the chariot. It does not follow that he was baptized by immersion. The text neither affirms nor intimates any thing concerning it.

Jamieson-Fausset-Brown Bible Commentary

38. they went down both into the water, and he baptized him, &c.-probably laving the water upon him, though the precise mode is neither certain nor of any consequence.

Matthew Henry's Concise Commentary

8:26-40 Philip was directed to go to a desert. Sometimes God opens a door of opportunity to his ministers in very unlikely places. We should study to do good to those we come into company with by travelling. We should not be so shy of all strangers as some affect to be. As to those of whom we know nothing else, we know this, that they have souls. It is wisdom for men of business to redeem time for holy duties; to fill up every minute with something which will turn to a good account. In reading the word of God, we should often pause, to inquire of whom and of what the sacred writers spake; but especially our thoughts should be employed about the Redeemer. The Ethiopian was convinced by the teaching of the Holy Spirit, of the exact fulfilment of the Scripture, was made to understand the nature of the Messiah's kingdom and salvation, and desired to be numbered among the disciples of Christ. Those who seek the truth, and employ their time in searching the Scriptures, will be sure to reap advantages. The avowal of the Ethiopian must be understood as expressing simple reliance on Christ for salvation, and unreserved devotion to Him. Let us not be satisfied till we get faith, as the Ethiopian did, by diligent study of the Holy Scriptures, and the teaching of the Spirit of God; let us not be satisfied till we get it fixed as a principle in our hearts. As soon as he was baptized, the Spirit of God took Philip from him, so that he saw him no more; but this tended to confirm his faith. When the inquirer after salvation becomes acquainted with Jesus and his gospel, he will go on his way rejoicing, and will fill up his station in society, and discharge his duties, from other motives, and in another manner than heretofore. Though baptized in the name of the Father, Son, and Holy Ghost, with water, it is not enough without the baptism of the Holy Ghost. Lord, grant this to every one of us; then shall we go on our way rejoicing.