דַּבֵּר אֶל־בְּנֵי יִשְׂרָאֵל וְיִקְחוּ־לִי תְּרוּמָה מֵאֵת כָּל־אִישׁ אֲשֶׁר יִדְּבֶנּוּ לִבּוֹ תִּקְחוּ אֶת־תְּרֽוּמָתִֽי
Speak to the people of Israel, that they bring me an offering; from every man that gives it willingly with his heart you shall take my offering.
Actually, all the gold and silver in the world belong to the Lord, as it is written: “Mine is the silver, and Mine the gold, says the Lord.” Hence, when man offers these things to God, the gift he gives is not the wealth, because that is not really his to give away. It is the willingness of his heart and his good intention that impelled him to make the offering. These qualities truly are his own, and that is what he should be offering to God.
One who does not make an offering of silver and gold in this spirit of goodwill has given nothing, because the money is not his to give away and the spirit of willingness, which would have been the true gift, is lacking. This is the meaning of the specification “of every man whose heart makes him willing”: Only from he whose gift is given out of willingness of heart and with good intentions shall you take My offering. Do not take anything from he whose heart does not make him willing to offer a gift to the Lord. (Menachem Tzion)