He knew there would be several groups of people that could be beneficial to the project. He needed the people that had the supplies to willingly give of them. He needed for the people that had the talent to build to use their knowledge to see the project completed. He knew that lacking either the willingness or knowledge would cause the tabernacle never to be built.
Today we look to build up a different type of tabernacle. We look to win people over to Jesus, converting them into temples of the Holy Spirit.
Just as there was diversity within the Israelite people there are many differing roles within the body of Christ: Preachers, teachers, prayer warriors, builders, visionaries, encouragers, givers, etc.
To be successful in building the kingdom of God two things are still required of his people: willingness to give of themselves and wisdom to grow in the Lord.