David really wanted to build the Temple:
28:2-3 … My brothers and my people! It was my desire to build a temple where the Ark of the Lord’s Covenant, God’s footstool, could rest permanently. I made the necessary preparations for building it, but God said to me, ‘You must not build a temple to honor my name, for you are a warrior and have shed much blood.’
So much so, that even though he couldn’t lay a stone, he gathered the building materials, made plans, divvied up the jobs amongst the Levites, and more. It seems David did everything except lay the stones.
To make sure Solomon had no doubt about whose project it really was, David added this little flourish:
28:19 Every part of this plan … was given to me in writing from the hand of the Lord.
I’m not sure just how much detail God really did tell David, or whether it was what he wanted God to tell him. After all, God’s clear instruction was:
28:6 Your son Solomon will build my Temple and its courtyards, for I have chosen him as my son, and I will be his father.
It’s hard to see what Solomon had left to do, other than lay stones. Following in his father’s footsteps would have been hard enough, but now he couldn’t even take any real initiative in the task God had set for him.