Disclaimer: I don't own Supernatural, that is Kripke's domain. I just play around in it.
I thought this up while reading Dostoevsky's Crime and Punishment, or rather, I finally figured out how to make this little theory work for me. It references John 11.
Spoilers up to Lazarus Rising, although there are some vague mentions made to most of seasons 4 and 5.
Dean Winchester was in hell for four months. Four months of torture, four months of pain.
He was the righteous man, the one who could start –and end- the apocalypse. He was valuable to heaven and so they tried to save him from the depths of hell. Yet they were limited, bound by the Rule of Fours.
Jesus Christ had resurrected Lazarus after four days, essentially by asking God to allow it to occur. The exact number was based on… well it was very much not based on anything important, just how long it would take them to get to Bethany. Such a thing relied upon rewriting the base code of the universe to allow proper resurrection to happen after 'fours' on Earth had happened.
The result was that now Angels could only resurrect people when a four _ since death was occurring. This had also effected when Angels could enter hell to fetch souls for resurrection.
The first attack on hell happened the fourth minute after Dean's death. The angels were unable to get to his soul in time and were kicked out of hell. The fourth hour came around and the second attempt failed as well. The fourth day came and passed, then the fourth week. They failed, failed, failed and failed, each time being summarily flung from the pit and left to wait until their next try could commence, for they were good soldiers and would obey their order: "Save Dean Winchester."
When the fourth month came around, a new garrison became involved, to supplement the numbers of angels who had been lost in previous attempts. The intrepid Angel of Thursday was among these new recruits and three weeks into the fight he drew upon the extra boost of powers the day gave him to flit through hell, sneaking rather than barging, to save Dean's soul.
Had God been around, He could have rewritten the base code again. Yet, had He chosen to involve himself, Dean might not have been reborn on a Thursday, or been raised by another angel. The Lord could have stopped his first children from plotting in the first place. Yet to change the storyline would be to make it so that Castiel did not raise Dean Winchester from hell, did not become a part of the extended Winchester family.
And He very well couldn't let that entertainment not happen, now could He?
