David called for a special collection; an offering; a passing of the plate. First, he described to the assembly what he had collected and what he had given (1st Chronicles 29:2-3). Then, with a reminder that the palace (temple) was " ...not for man, but for God," David invited his people to give toward the completion of the project.
Notice the manner in which the people gave. Most importantly, the people didn't give grudgingly or vainly. They didn't have to be coerced to give... 1st Chronicles 29:6 says that what they gave, they offered willingly. And, they didn't give out-of-style clothing, canned pumpkin or worn out vacuum cleaners. They gave gold, silver, brass, iron and precious stones. And 1st Chronicles 29:9 says that " ...the people rejoiced ... because with perfect heart they offered willingly to the LORD..."
Now, check out the vitally poignant thought that is tucked away in verse 15. Concerning returning God's own things to Him, David prayed, "We are strangers before thee, and sojourners... our days on the earth are as a shadow, and there is none abiding." Gifts from a shadow... meditate on that! When you and I are dead and gone we will have had little more effect on this world than a shadow has when it passes over the ground. Now, what tangible contribution can a shadow make? Well, momentary refreshment perhaps, that about it.
So anyway, David called for an offering and commanded his people to worship (1st Chronicles 29:20)... as 3000 animals were killed, bled and burned before God on that day. Then, David begged God to bless Solomon with a good heart. At the end of this chapter, Solomon was king, David was in Paradise and God was honored.