To literally cross the firmament between this earth and Heaven (Genesis 1:1-8, 14-18): from mortality to immortality or from death to Eternal Life requires a CROSS: the CROSS of JESUS CHRIST, the only begotten Son of God (John 3:16-18) who says:
‘If any man will come after me, let him deny himself, and take up his [CROSS], and follow me’” (Matthew 16:24). “And he that taketh not his cross, and followeth after me, is not worthy of me” (Matthew 10:38).
“I am the resurrection, and the life: he that believeth in me, though he were dead, yet shall he live; and whosoever liveth and believeth in me shall never die. Believest thou this?” (John 11:25-27).
“I am the door: by me if any man enter in, he shall be saved, and shall go in and out, and find pasture” (John 10:9).
“I am he that liveth, and was dead; and, behold, I am alive for evermore, Amen; and have the keys of hell and of death” (Revelation 1:18).
“I am the way, the truth, and the life: no man cometh unto the Father, but by me” (John 14:6).