Hi Paul,
 
When the Third Temple is rebuilt, there will be daily sacrifices again made for the Jewish people's sins.  However, Jesus was the one pure sacrifice for the sins of the world, and there will be no more sacrifice for sin because Hebrews 10:10-12 says, "By the which will we are sanctiified through the offering of the body of Jesus Christ once for all. And every priest standeth daily ministering and offering oftentimes the same sacrifices, which can never take away sins: But this man, after he had offered one sacrifice for sins for ever, sat down on the right hand of God; from henceforth expecting till his enemies be made his footstool. For by one offereing he hath perfected for ever them that are sanctified."
 
So the question is why would you want to donate money to help rebuild a temple where there will be daily sacrifices for the Jewish people's sins when the "one sacrifice for sins forever" was already made by Jesus Christ. I certainly wouldn't want to help rebuild the Third Temple because I think it would show unbelief in the word of God that Jesus was "the one sacrifice for sins forever," and I also wouldn't want to personally donate money to help build a temple where the son of perdition is going to sit and proclaim himself to be God.  Let some unbeliever pay for the seat and the chair that is going to hold his evil and vile carcass.
 
God bless,
Donna