The emphasis on the willing hearts of the people is unmistakable in this passage. Exodus 35:5, 21, 22, 26 & 29 all speak conspicuously of the role of the willing heart in the donations which were to be made for the Tabernacle. If all you see in this chapter is a grocery list of the items which were given in order to construct the sanctuary, well, then you have missed the highlight of the text. We need to go further than the offering total. We need to see why the people gave (II Corinthians 9:7).
Not to imply that God didn't affect the hearts of all of these people... quite the contrary is true. Exodus 35:34-35 indicate plainly that God put abilities in these people; that HE filled them with wisdom and desire. No surprise of course...this section features the great mystery of God's wonderful sovereignty and the genuine prerogatives of men (Proverbs 16:9, Genesis 24:27, Jeremiah 10:23 & Psalm 37:23). Obviously these people's hearts couldn't have been so noble without God's influence (Jeremiah 17:9, Romans 3:11 & Psalm 51:10). We are always ill equipped, yet liable... and, He is always fully equipped and able ... hence the necessity of our reliance upon Him.