Charles Spurgeon Commentary Acts 8:12-17

"But when they believed Philip preaching good tidings concerning the kingdom of God and the name of Jesus Christ, they were baptized, both men and women. And Simon also himself believed: and being baptized, he continued with Philip; and beholding signs and great miracles wrought, he was amazed. Now when the apostles that were at Jerusalem heard that Samaria had received the word of God, they sent unto them Peter and John: who, when they were come down, prayed for them, that they might receive the Holy Spirit: for as yet it was fallen upon none of them: only they had been baptized into the name of the Lord Jesus. Then laid they their hands on them, and they received the Holy Spirit." — Acts 8:12-17 (ASV)

But when they believed Philip preaching the things concerning the kingdom of God, and the name of Jesus Christ, they were baptized, both men and women. Then Simon himself believed also: and when he was baptized, he continued with Philip, and wondered, beholding the miracles and signs which were done. Now when the apostles which were at Jerusalem heard that Samaria had received the word of God, they sent unto them Peter and John: who, when they were come down, prayed for them, that they might receive the Holy Ghost: (for as yet he was fallen upon none of them: only they were baptized in the name of the Lord Jesus.) Then laid they their hands on them, and they received the Holy Ghost.

So, miraculous gifts were bestowed upon them. Of course, there was already manifest among them that divine operation of the Spirit of God, by which people are converted and brought to faith in Christ; but they had not known the special, attesting, wonder-working power of the Spirit until the apostles came among them.

So, a good work was done, yet everything was not altogether as the apostles could have wished it to be.