1Now the boy Samuel was ministering to the Lord under Eli. The word of the Lord was rare in those days; visions were not widespread.
2 At that time Eli, whose eyesight had begun to grow dim so that he could not see, was lying down in his room; 3the lamp of God had not yet gone out, and Samuel was lying down in the temple of the Lord, where the ark of God was. 4Then the Lord called, ‘Samuel! Samuel!’ and he said, ‘Here I am!’ 5and ran to Eli, and said, ‘Here I am, for you called me.’ But he said, ‘I did not call; lie down again.’ So he went and lay down. 6The Lord called again, ‘Samuel!’ Samuel got up and went to Eli, and said, ‘Here I am, for you called me.’ But he said, ‘I did not call, my son; lie down again.’ 7Now Samuel did not yet know the Lord, and the word of the Lord had not yet been revealed to him. 8The Lord called Samuel again, a third time. And he got up and went to Eli, and said, ‘Here I am, for you called me.’ Then Eli perceived that the Lord was calling the boy. 9Therefore Eli said to Samuel, ‘Go, lie down; and if he calls you, you shall say, “Speak, Lord, for your servant is listening.” ’ So Samuel went and lay down in his place.
10 Now the Lord came and stood there, calling as before, ‘Samuel! Samuel!’ And Samuel said, ‘Speak, for your servant is listening.’
And the Lord came, and stood, and called as at other times, Samuel, Samuel. Then Samuel answered, Speak, for thy servant heareth.
In the narrative of which these words form part, we have a remarkable instance of a divine call, and the manner in which it is our duty to meet it. Samuel was from a child brought to the house of the Lord; and in due time he was called to a sacred office, and made a prophet. He was called, and he forthwith answered the call. God said, Samuel, Samuel. He did not understand at first who called, and what was meant; but on going to Eli he learned who spoke, and what his answer should be. So when God called again, he said, Speak, Lord, for thy servant heareth. Here is prompt obedience.
Or consider the circumstances of the call of Abraham, the father of all who believe. He was called from his father's house, but was not told whither. Saint Paul was told to go to Damascus, and there he was to receive further directions. In like manner Abraham left his home for a land that I will show thee, says almighty God. Accordingly he went out, not knowing whither he went. Abram departed as the Lord had spoken unto him.
Such are the instances of divine calls in scripture, and their characteristic is this; to require instant obedience, and next to call us we know not to what; to call us on in the darkness. Faith alone can obey them.
And these divine calls are commonly, from the nature of the case, sudden now, and as indefinite and obscure in their consequences as in former times. The accidents and events of life are, as is obvious, one special way in which the calls I speak of come to us; and they, as we all know, are in their very nature, and as the word accident implies, sudden and unexpected. We are going on as usual; we come home one day and find a letter, or a message, or a person, whereby a sudden trial comes on us, which, if met religiously, will be the means of advancing us to a higher state of religious excellence, which at present we as little comprehend as the unspeakable words heard by Saint Paul in paradise. By a trial we commonly mean a something which, if encountered well, will confirm us in our present way; but I am speaking of something more than this, of what will not only confirm us, but raise us into a high state of knowledge and holiness.
God is leading forward his redeemed, he is training his elect, one and all, to the one perfect knowledge and obedience of Christ; not, however, without their cooperation, but by means of calls which they are to obey, and which if they do not obey, they lose place, and fall behind in their heavenly course. He leads them forward from strength to strength, and from glory to glory, up the steps of the ladder whose top reaches to heaven. We pass from one state of knowledge to another; we are introduced into a higher region from a lower, by listening to Christ's call and obeying it.
Newman's words do not exactly answer the problem of how we know that it's God's voice calling to us, but I though they were worth our consideration. In any case, the passage from 1 Samuel is a good reminder of what prayer in troubled times should be: Not so much "Listen, Lord, your servant is speaking!" but rather "Speak, Lord, your servant is listening!" Happy listening...