The revelation of God comes to all men in Nature, History, and it is written into the heart of all men.
Ps 19:1 The heavens declare the glory of God; And the firmament shows His handiwork. 2 Day unto day utters speech, And night unto night reveals knowledge. 3 There is no speech nor language Where their voice is not heard. 4 Their line has gone out through all the earth, And their words to the end of the world. Isa 40:26 Lift up your eyes on high, And see who has created these things, Who brings out their host by number; He calls them all by name, By the greatness of His might And the strength of His power; Not one is missing. NKJV
God is the source of all revelation.
Dan 2:27 Daniel answered in the presence of the king, and said, "The secret which the king has demanded, the wise men, the astrologers, the magicians, and the soothsayers cannot declare to the king. 28 But there is a God in heaven who reveals secrets, and He has made known to King Nebuchadnezzar what will be in the latter days. Your dream, and the visions of your head upon your bed, were these: 29 As for you, O king, thoughts came to your mind while on your bed, about what would come to pass after this; and He who reveals secrets has made known to you what will be. 30 But as for me, this secret has not been revealed to me because I have more wisdom than anyone living, but for our sakes who make known the interpretation to the king, and that you may know the thoughts of your heart. NKJV
Only Jesus can reveal the heart of God.
John 1:18 No man has ever seen God at any time; the only unique Son, or the only begotten God, Who is in the bosom [in the intimate presence] of the Father, He has declared Him [He has revealed Him and brought Him out where He can be seen; He has interpreted Him and He has made Him known] AMP
We believers have been entrusted with the Spirit of revelation.
1 Cor 2:6 However, we speak wisdom among those who are mature, yet not the wisdom of this age, nor of the rulers of this age, who are coming to nothing. 7 But we speak the wisdom of God in a mystery, the hidden wisdom which God ordained before the ages for our glory, 8 which none of the rulers of this age knew; for had they known, they would not have crucified the Lord of glory.
9 But as it is written:
"Eye has not seen, nor ear heard, Nor have entered into the heart of man The things which God has prepared for those who love Him." 10 But God has revealed them to us through His Spirit. For the Spirit searches all things, yes, the deep things of God. 11 For what man knows the things of a man except the spirit of the man which is in him? Even so no one knows the things of God except the Spirit of God. 12 Now we have received, not the spirit of the world, but the Spirit who is from God, that we might know the things that have been freely given to us by God. 13 These things we also speak, not in words which man’s wisdom teaches but which the Holy Spirit teaches, comparing spiritual things with spiritual. 14 But the natural man does not receive the things of the Spirit of God, for they are foolishness to him; nor can he know them, because they are spiritually discerned. 15 But he who is spiritual judges all things, yet he himself is rightly judged by no one. 16 For "who has known the mind of the Lord that he may instruct Him?" But we have the mind of Christ. NKJV
The Apostle prayed that all believers would operate in the Spirit of Wisdom and Revelation.
Eph 1: 15 Therefore I also, after I heard of your faith in the Lord Jesus and your love for all the saints, 16 do not cease to give thanks for you, making mention of you in my prayers: 17 that the God of our Lord Jesus Christ, the Father of glory, may give to you the spirit of wisdom and revelation in the knowledge of Him, 18 the eyes of your understanding being enlightened; that you may know what is the hope of His calling, what are the riches of the glory of His inheritance in the saints, 19 and what is the exceeding greatness of His power toward us who believe, according to the working of His mighty power 20 which He worked in Christ when He raised Him from the dead and seated Him at His right hand in the heavenly places, 21 far above all principality and power and might and dominion, and every name that is named, not only in this age but also in that which is to come. 22 And He put all things under His feet, and gave Him to be head over all things to the church, 23 which is His body, the fullness of Him who fills all in all.
The Apostle prayed that all believers would make known the Mystery of the plan of God in salvation with power.
Eph 3:8 To me, who am less than the least of all the saints, this grace was given, that I should preach among the Gentiles the unsearchable riches of Christ, 9 and to make all see what is the fellowship of the mystery, which from the beginning of the ages has been hidden in God who created all things through Jesus Christ; 10 to the intent that now the manifold wisdom of God might be made known by the church to the principalities and powers in the heavenly places, 11 according to the eternal purpose which He accomplished in Christ Jesus our Lord, 12 in whom we have boldness and access with confidence through faith in Him. 13 Therefore I ask that you do not lose heart at my tribulations for you, which is your glory.
14 For this reason I bow my knees to the Father of our Lord Jesus Christ, 15 from whom the whole family in heaven and earth is named, 16 that He would grant you, according to the riches of His glory, to be strengthened with might through His Spirit in the inner man, 17 that Christ may dwell in your hearts through faith; that you, being rooted and grounded in love, 18 may be able to comprehend with all the saints what is the width and length and depth and height — 19 to know the love of Christ which passes knowledge; that you may be filled with all the fullness of God.
20 Now to Him who is able to do exceedingly abundantly above all that we ask or think, according to the power that works in us, 21 to Him be glory in the church by Christ Jesus to all generations, forever and ever. Amen. NKJV
Col 1:27 To them God willed to make known what are the riches of the glory of this mystery among the Gentiles: which is Christ in you, the hope of glory. NKJV
Simon Peter had been used by God in bringing 3000 people to salvation on the day of Pentecost.
But, Simon Peter needed even more revelation from heaven for what he would encounter next.
Acts 10: 9 The next day, as they went on their journey and drew near the city, Peter went up on the housetop to pray, about the sixth hour. 10 Then he became very hungry and wanted to eat; but while they made ready, he fell into a trance 11 and saw heaven opened and an object like a great sheet bound at the four corners, descending to him and let down to the earth. 12 In it were all kinds of four‑footed animals of the earth, wild beasts, creeping things, and birds of the air. 13 And a voice came to him, "Rise, Peter; kill and eat." 14 But Peter said, "Not so, Lord! For I have never eaten anything common or unclean."
15 And a voice spoke to him again the second time, "What God has cleansed you must not call common." 16 This was done three times. And the object was taken up into heaven again.
17 Now while Peter wondered within himself what this vision which he had seen meant, behold, the men who had been sent from Cornelius had made inquiry for Simon’s house, and stood before the gate. 18 And they called and asked whether Simon, whose surname was Peter, was lodging there.
19 While Peter thought about the vision, the Spirit said to him, "Behold, three men are seeking you. 20 Arise therefore, go down and go with them, doubting nothing; for I have sent them."
21 Then Peter went down to the men who had been sent to him from Cornelius, and said, "Yes, I am he whom you seek. For what reason have you come?"
22 And they said, "Cornelius the centurion, a just man, one who fears God and has a good reputation among all the nation of the Jews, was divinely instructed by a holy angel to summon you to his house, and to hear words from you." 23 Then he invited them in and lodged them. NKJV