There are many cases in scripture where a prophet was addressed by the Almighty. While this at times came through the agency of an angel, there are other times when the contact was more direct.
In Genesis 6 we read, “13 So God said to Noah, ‘I am going to put an end to all people, for the earth is filled with violence because of them. I am surely going to destroy both them and the earth. 14 So make yourself an ark of cypress wood; make rooms in it and coat it with pitch inside and out. . . . 22 Noah did everything just as God commanded him’.” There is no conversation. Noah hears God, and obeys.
Similarly in Genesis 12: 1f, “The Lord had said to Abram, ‘Go from your country, your people and your father’s household to the land I will show you. . . .’ 4 So Abram went, as the Lord had told him; and Lot went with him. Abram was seventy-five years old when he set out from Harran.” Again, speechless obedience.
This is not to say that Abram/Abraham did not speak to God. There is the example of Genesis 18:16-33 where the patriarch pleads with God. But his obedience is shown time and again, culminating with the sacrifice account of Genesis 22:1-19.
Samuel gives us another insight. In I Samuel 3 we read, “The boy Samuel ministered before the Lord under Eli. In those days the word of the Lord was rare; there were not many visions.2 One night Eli, whose eyes were becoming so weak that he could barely see, was lying down in his usual place. 3 The lamp of God had not yet gone out, and Samuel was lying down in the house of the Lord, where the ark of God was. 4 Then the Lord called Samuel. Samuel answered, “Here I am.” 5 And he ran to Eli and said, “Here I am; you called me.” But Eli said, “I did not call; go back and lie down.” So he went and lay down.6 Again the Lord called, “Samuel!” And Samuel got up and went to Eli and said, “Here I am; you called me.” “My son,” Eli said, “I did not call; go back and lie down.” 7 Now Samuel did not yet know the Lord: The word of the Lord had not yet been revealed to him. 8 A third time the Lord called, “Samuel!” And Samuel got up and went to Eli and said, “Here I am; you called me.” Then Eli realized that the Lord was calling the boy. 9 So Eli told Samuel, “Go and lie down, and if he calls you, say, ‘Speak, Lord, for your servant is listening.’” So Samuel went and lay down in his place. 10 The Lord came and stood there, calling as at the other times, “Samuel! Samuel!” Then Samuel said, “Speak, for your servant is listening.”
“SPEAK, FOR YOUR SERVANT IS LISTENING.” Three times he runs to attend to his teacher and master. He was attentive, conscientious, and loyal. And the Lord spoke again. He was ready. He was listening. He heard and responded to the Voice. Are we that open to a call. Noah, Abraham, and Samuel were ready.
Isaiah goes a step further. He too listened. But not only obeyed, but volunteered! “Then I [Isaiah] heard the voice of the Lord saying, ‘Whom shall I send? And who will go for us?’ And I said, ‘Here am I. Send me!'”
How will you respond when called? Are you listening?