Purgatory

Catholics believe there is an intermediate place between Heaven and Hell known as Purgatory, where you serve time before going on to Heaven.

Sheol
In reality, the Old Testament declares a place known as "Sheol", also called "the Grave" and "the Pit", was where the dead would go. It was said to be a land of darkness and the shadow of death, where the wicked cease from troubling, a place of rest where life is forgotten, and both prisoners and the kings of the earth rest together.

Job 3:11 Why died I not from the womb? why did I not give up the ghost when I came out of the belly? 12 Why did the knees prevent me? or why the breasts that I should suck? 13 For now should I have lain still and been quiet, I should have slept: then had I been at rest, 14 With kings and counsellors of the earth, which built desolate places for themselves; 15 Or with princes that had gold, who filled their houses with silver: 16 Or as an hidden untimely birth I had not been; as infants which never saw light. 17 There the wicked cease from troubling; and there the weary be at rest. 18 There the prisoners rest together; they hear not the voice of the oppressor. 19 The small and great are there; and the servant is free from his master.

Job 10:21 Before I go whence I shall not return, even to the land of darkness and the shadow of death; 22 A land of darkness, as darkness itself; and of the shadow of death, without any order, and where the light is as darkness.

Job 17:13 If I wait, the grave is mine house: I have made my bed in the darkness.

Ecclesiastes 9:10 Whatsoever thy hand findeth to do, do it with thy might; for there is no work, nor device, nor knowledge, nor wisdom, in the grave, whither thou goest.

Psalms 88:3 For my soul is full of troubles: and my life draweth nigh unto the grave. 4 I am counted with them that go down into the pit: I am as a man that hath no strength: 5 Free among the dead, like the slain that lie in the grave, whom thou rememberest no more: and they are cut off from thy hand. 6 Thou hast laid me in the lowest pit, in darkness, in the deeps.

Psalms 88:10 Wilt thou shew wonders to the dead? shall the dead arise and praise thee? Selah. 11 Shall thy lovingkindness be declared in the grave? or thy faithfulness in destruction? 12 Shall thy wonders be known in the dark? and thy righteousness in the land of forgetfulness?

Isaiah 14:9 Hell from beneath is moved for thee to meet thee at thy coming: it stirreth up the dead for thee, even all the chief ones of the earth; it hath raised up from their thrones all the kings of the nations. 10 All they shall speak and say unto thee, Art thou also become weak as we? art thou become like unto us? 11 Thy pomp is brought down to the grave, and the noise of thy viols: the worm is spread under thee, and the worms cover thee.

An Impassable Gulf
Jesus spoke of Sheol, saying it is composed of two parts, one for the wicked, and one for the just, and quoted Abraham as saying,"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."

Luke 16:25 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.

Lowest Hell
While there is a "lowest hell" spoken of there is no indication whatsoever of those in it or in hell in general being able to pass over to the other side where Abraham is, indeed such would directly contradict Luke 16:26.

Deuteronomy 32:22 For a fire is kindled in mine anger, and shall burn unto the lowest hell, and shall consume the earth with her increase, and set on fire the foundations of the mountains. Psalms 86:13 For great is thy mercy toward me: and thou hast delivered my soul from the lowest hell.

Conclusion
Biblically, there is no gradual changing from one to the other as you "serve time" as it were. Instead, there is simply a once-for-all Final Judgment where the sea, death, and hell all give up the dead that are in them, and each is judged according to their works - death and hell get cast into the Lake of Fire along with those not written in Jesus' Book of Life by being "born again".

Revelation 20:13 And the sea gave up the dead which were in it; and death and hell delivered up the dead which were in them: and they were judged every man according to their works. 14 And death and hell were cast into the lake of fire. This is the second death. 15 And whosoever was not found written in the book of life was cast into the lake of fire.