(Numb. 7:2:) “Now the princes of Israel drew near (to make an offering).” You find that when Moses proclaimed and said (in Exod. 35:5), “Take from among you an offering [for the Lord],” what did the princes do? They said, “Moses did not know [enough] to tell us that the Tabernacle was being made.” What did they do?
They did not give a freewill offering. They said, “These people are making the Tabernacle, and now he is telling us to give a freewill offering?” The Holy One, blessed be He, said, “By your lives, you should know that I do not need you (princes).” What is written there (in Exod. 36:3)?
“And they (i.e., the Children of Israel) still brought freewill offerings unto him in the morning, in the morning.” R. Johanan said, “For two mornings they brought all the supplies (mela'khah) for the Tabernacle, and they were more than enough, as stated (in Exod. 36:7), ‘For they had sufficient supplies (mela'khah), more than enough for all the work (mela'khah) to make it.’”
And it is written (in Exod. 39:43), “When Moses saw all the work (mela'khah) […]; then Moses blessed them.” And with what blessing did he bless them? He said to them, “May the Divine Presence dwell in the work of your hands.” In this world Moses has blessed them; but in the world to come, the Holy One, blessed be He, will bless them, as stated (in Ps. 128:5–6), “The Lord will bless you from Zion; may you see the prosperity of Jerusalem…!”