Or HaChaim on Exodus 36:5/אור החיים על שמות ל״ו:ה׳

1 מרבים העם להביא; the people were bringing too much. Why would it be such a bad thing for the Temple treasury to possess a good supply? We should not understand the artisans' comments as a complaint that too much raw material had been contributed; they complained that too much material such as fabrics already woven or embroidered had been brought. They were neither required nor likely to be safe against deterioration. This sentiment was expresseed in the words מרבים…מדי העבודה, more than could be put to use immediately. Further proof that our interpretation is correct may be seen in the proclamation to the people not to perform any more work designed to be used in the construction of the Sanctuary. Moses did not discourage donations of raw materials. When the Torah states that the people were prevented from bringing more materials and not from performing more work such as weaving fabrics, the reason is that Betzalel had no control over what people did within their tents.