Peter was praying on a rooftop (Acts 10:9) and several miles away another man, Cornelius, also was praying. “There was a certain man in Caesarea called Cornelius, a centurion of the band called the Italian band, a devout man, and one that feared God with all his house, which gave much alms to the people, and prayed to God alway. He saw in a vision evidently about the ninth hour of the day an angel of God coming in to him, and saying unto him, Cornelius. And when he looked on him, he was afraid, and said, What is it, Lord? And he said unto him, Thy prayers and thine alms are come up for a memorial before God. And now send men to Joppa, and call for one Simon, whose surname is Peter. He lodgeth with one Simon a tanner, whose house is by the sea side: he shall tell thee what thou oughtest to do” (Acts10:1-6). What detailed instructions!
Meanwhile, Peter had a vision. “While Peter thought on the vision, the Spirit said unto him, Behold, three men seek thee. . . . Go with them . . . for I have sent them” (Acts 10:19-20). Peter went to the house of Cornelius and met a praying man. “And Cornelius said, Four days ago I was fasting until this hour; and at the ninth hour I prayed in my house, and, behold, a man stood before me in bright clothing, and said, Cornelius, thy prayer is heard. . . . Send therefore to Joppa, and call hither Simon, whose surname is Peter; he is lodged in the house of one Simon a tanner by the sea side: who, when he cometh, shall speak unto thee. Immediately therefore I sent to thee; and thou hast well done that thou art come. Now therefore are we all here present before God, to hear all things that are commanded thee of God” (Acts 10:30-33). The Holy Ghost was so specific He even gave both names: “Call Simon, whose surname is Peter” (verse 32).
All through Acts we read these words, “God said to them . . . The Lord said . . . The Holy Ghost said . . . The angel said. . . .” Heaven was not closed. They received the clear mind of the Lord, very practical, detailed and clear. But the word from heaven came only after much prayer, after being shut up alone with God in secret.