The Torah relates Hashem telling Moshe to take donations from the people Mikol Asher Yidvenu Libo (from all whose hearts donate) you should take the donation.
The purpose of this donation is for the building of the Mishkan.
The use of the term "Whose heart donates" is very unusual. Just say that from whoever gives a donation you should take it? Why Asher Yidvenu libo?
I think the idea is that this is not the same as the regular mitzva of tzedaka. Normally you have a mitzva of tzedakka and you give sometimes reluctantly and sometimes happily. A guy shows up at your door and asks for tzedaka and you either give him or don't, but if you do he takes it and you have fullfilled your mitzva of tzedaka, even if you gave it reluctantly.
Here we are dealing with the building of a sanctuary for Hashem. A mikdash. This applies to the Mikdash, as well as to the mikdash me'ats we are obligated to build, in the form of shuls, yeshivos, day schools, and our own homes dedicated to the ideals of the Torah. This is not like the average mitzva of tzedakka. This is special. this is the foundation of the Jewish nation. Everything comes from the Mikdash in all its forms.
Donations cannot just be accepted from anybody who was pressured into donation and coerced into giving. This has to come from the heart. People have to want to participate in the building of the foundation of the jewish nation. Not be coerced into it. When the building of our mikdashei me'at are done from goodwill and desire of participation, they have the greatest chance of success and continuation, as that makes everybody a partner in the mikdash.