In the Gospel of Luke we find the story of the Rich Man and Lazarus.
19 There was a certain rich man, which was clothed in purple and fine linen, and fared sumptuously every day: 20 And there was a certain beggar named Lazarus, which was laid at his gate, full of sores, 21 And desiring to be fed with the crumbs which fell from the rich man's table: moreover the dogs came and licked his sores. 22 And it came to pass, that the beggar died, and was carried by the angels into Abraham's bosom: the rich man also died, and was buried; 23 And in hell he lift up his eyes, being in torments, and seeth Abraham afar off, and Lazarus in his bosom. 24 And he cried and said, Father Abraham, have mercy on me, and send Lazarus, that he may dip the tip of his finger in water, and cool my tongue; for I am tormented in this flame. 25 But Abraham said, Son, remember that thou in thy lifetime receivedst thy good things, and likewise Lazarus evil things: but now he is comforted, and thou art tormented. 26 And beside all this, between us and you there is a great gulf fixed: so that they which would pass from hence to you cannot; neither can they pass to us, that [would come] from thence. 27 Then he said, I pray thee therefore, father, that thou wouldest send him to my father's house: 28 For I have five brethren; that he may testify unto them, lest they also come into this place of torment. 29 Abraham saith unto him, They have Moses and the prophets; let them hear them. 30 And he said, Nay, father Abraham: but if one went unto them from the dead, they will repent. 31 And he said unto him, If they hear not Moses and the prophets, neither will they be persuaded, though one rose from the dead.
In this story told by Christ, we find that the rich man is in Hades, and that he is in tormented in the flames. The rich man personally described this place, as a place of torment. It is this Hades, which is cast into the Lake of Fire, which is the second death.
The first and second death is what Paul refers to in Romans 6:23,
23 For the wages of sin [is] death; but the gift of God [is] eternal life through Jesus Christ our Lord.
Physical death, however, is not a sufficient payment for sins, as the Voice of Prophecy implies. If physical death was sufficient to pay the debt of sin, then Christ died in vain, and everyone who dies should be promoted to heaven and no man would go to Hades or the Lake of Fire, since his sin debt is paid at his physical death.