If the Holy Spirit is to be given only through the apostles' laying their hands; why did the Holy Spirit come on Cornelius and his house before they got baptized by St. Peter (Acts 10)?
In this particular incident, God was introducing the Gentiles to the faith, and was sending a new and strong message to the Jewish believers. This message was that the long awaited Messiah, promised to the Israelis, has come for the gentiles as well who have a share in Him as much as they do. "While Peter was still speaking these words, the Holy Spirit fell upon all those who heard the word. And those of the circumcision who believed were astonished, as many as came with Peter, because the gift of the Holy Spirit had been poured out on the Gentiles also. For they heard them speak with tongues and magnify God" (Acts 10:44-46).
When the Holy Spirit fell upon them while Peter was preaching; God bore witness to what he had said, and accompanied it with a divine power. That is why we see those Gentiles speaking with tongues; magnifying God. When reading the Holy Bible, we should be aware of the danger of using one single verse out of or detached from context. We cannot take that verse to mean that there is no need for the laying of hands. We read in case of the Samaritans "Now when the apostles who were at Jerusalem heard that Samaria had received the word of God, they sent Peter and John to them, who, when they had come down, prayed for them that they might receive the Holy Spirit. For yet He had fallen upon none of them. They had only been baptized in the name of the Lord Jesus. Then they laid hands on them, and they received the Holy Spirit" (Acts 8:14-17).
Also St. Paul with the Ephesians "He said to them, "Did you receive the Holy Spirit when you believed?" So they said to him, "We have not so much as heard whether there is a Holy Spirit... When they heard this, they were baptized in the name of the Lord Jesus. And when Paul had laid hands on them, the Holy Spirit came upon them, and they spoke with tongues and prophesied" (Acts 19:1-6).