And he commanded them to be baptized in the name of the Lord.

God called Peter to go to the Gentiles and preach the Gospel to them.

When Peter went into the house of Cornelius, he had “called together his kinsmen and near friends.”

Peter began preaching to them Jesus. He preached the gospel to them.

"And we are witnesses of all things which he did both in the land of the Jews, and in Jerusalem; whom they slew and hanged on a tree: Him God raised up the third day, and shewed him openly;" - Acts 10:39-40 KJV

"To him give all the prophets witness, that through his name whosoever believeth in him shall receive remission of sins." - Acts 10:43 KJV ["He is the one all the prophets testified about, saying that everyone who believes in him will have their sins forgiven through his name."" NLT]

"While Peter yet spake these words, the Holy Ghost fell on all them which heard the word. And they of the circumcision which believed were astonished, as many as came with Peter, because that on the Gentiles also was poured out the gift of the Holy Ghost. For they heard them speak with tongues, and magnify God." - Acts 10:44-46 KJV

Peter and the Jewish believers that came with Peter knew the Gentiles received the Holy Ghost because they heard them speak with tongues.

"Then answered Peter, Can any man forbid water, that these should not be baptized, which have received the Holy Ghost as well as we? And he commanded them to be baptized in the name of the Lord." - Acts 10:46-48 KJV

Why did Peter immediately COMMAND them to be baptized in the name of Jesus?

The Gentiles had received the promised GIFT of the covenant without entering into the covenant. The covenant is entered into when we are baptized in the name of Jesus and His blood is applied to our life. Peter preached about the promised gift on the Day of Pentecost:

"Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost. For the promise is unto you, and to your children, and to all that are afar off, even as many as the Lord our God shall call." - Acts 2:38-39 KJV