Jesus teaches against soul sleep

Many people argue that soul and spirit are unified with the body so that we never leave the body.  Many jewish groups as well as law-keeping christian sects teach this doctrine. One of which was the  Saducees.  jesus debates them directly regarding this issue
mark 11: ¹⁸ Then come unto him the Sadducees, which say there is no resurrection; and they asked him, saying,
¹⁹ Master, Moses wrote unto us, If a man's brother die, and leave his wife behind him, and leave no children, that his brother should take his wife, and raise up seed unto his brother.
²⁰ Now there were seven brethren: and the first took a wife, and dying left no seed.
²¹ And the second took her, and died, neither left he any seed: and the third likewise.
²² And the seven had her, and left no seed: last of all the woman died also.
²³ In the resurrection therefore, when they shall rise, whose wife shall she be of them? for the seven had her to wife.
²⁴ And Jesus answering said unto them, Do ye not therefore err, because ye know not the scriptures, neither the power of God?
²⁵ For when they shall rise from the dead, they neither marry, nor are given in marriage; but are as the angels which are in heaven.
²⁶ And as touching the dead, that they rise: have ye not read in the book of Moses, how in the bush God spake unto him, saying, I am the God of Abraham, and the God of Isaac, and the God of Jacob?
²⁷ He is not the God of the dead, but the God of the living: ye therefore do greatly err."
Now the Sadducees here, deny the resurrection and by implication any life after death.  Jesus first indicates that the resurrection is different than this life. Marriage and reproduction will no longer be needed.   But then he adds something at the end.  God is a God of the living, referring to Abraham Isaac and Jacob.  This implies that Abraham Isaac and Jacob are alive in the spiritual realm.
This is also agreed upon in the Old Testament.
Genesis 49:
³³ And when Jacob had made an end of commanding his sons, he gathered up his feet into the bed, and yielded up the ghost, and was gathered unto his people.
It is obvious that Jesus did not believe in soul sleep.