Hi!
(Slightly different version of your dream-if it isn't appropo, just toss)..
This dream of the mattress is similar to one I had many years ago, while still married.. (not anymore) We had a rough marriage. One night I had a dream of two mattresses, both on the ground. One was white and clean, ready to use, the other was full of worms/maggots. My husband was told to choose between the two, he choose the one with maggots. He wasn't living a sinless life at the time, although in church and preaching. He continued in his sin, eventually leaving the ministry and me. I take it he was comfortable in the 'bed/mattress (life/choices/decisions) that he made'..
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Psalm 139:8 'If I ascend up into heaven, thou art there: if I
make my bed in hell, behold, thou art there'. (Wherever I have made my thoughts comfortable, sin or righteousness, GOD is still there)..
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Job 7:13'When I say, My bed shall
comfort me, my couch shall ease my complaints'; (Ease my complaints, where one is most comfortable in his/her thoughts).
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John 5:8 Jesus saith unto him, Rise,
take up thy bed, and walk. ( could mean get rid of issues, give them to me (Jesus) and walk in the spirit).
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'Made your bed and lie in it definition': You made a decision and now must accept its consequences. Note : This expression is commonly used as a response to people who have been complaining about problems they have brought on themselves. *Dictionary.com Said to someone who must accept the unpleasant results of something they have done. *Cambridge Dictionary
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While it is hard to give an interp because you didn't state if anything was going on, in my opinion what you saw was symbolic. A mattress/bed is supposed to be a place of comfort/rest. Or could even represent a place in one's mind. Which These are just my thoughts, I hope I made them clear enough..
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Blessings