# the contributions lifted up to me

"the offerings that people give to me" 

# I have given these offerings to you

"I give these offerings to you". The tribes of Israel were required to bring a tithe (offering) to the Levites in order to free them to serve Yahweh as priests. There is a detailed description of what belonged to Yahweh in this chapter.

# as your assigned portion for all time

"as the portion that you will continually receive"