Exodus 34 and 35 recount the gathering of materials necessary to build the tabernacle and everything that goes with it. At the beginning of chapter 36 we find these words:
 And they received from Moses all the contribution that the people of Israel had brought for doing the work on the sanctuary. They still kept bringing him freewill offerings every morning,  so that all the craftsmen who were doing every sort of task on the sanctuary came, each from the task that he was doing,  and said to Moses, “The people bring much more than enough for doing the work that the LORD has commanded us to do.”  So Moses gave command, and word was proclaimed throughout the camp, “Let no man or woman do anything more for the contribution for the sanctuary.” So the people were restrained from bringing,  for the material they had was sufficient to do all the work, and more.
(Exodus 36:3-7 ESV)
Did you catch it?
The men in charge of the construction received everything they needed, yet people kept brining things every day. It was so overwhelming that the builders asked Moses to tell everyone to stop bringing supplies! And this is not the last time that this happened in scripture. Listen to what Paul says to the Corinthians:
 We want you to know, brothers, about the grace of God that has been given among the churches of Macedonia,  for in a severe test of affliction, their abundance of joy and their extreme poverty have overflowed in a wealth of generosity on their part.  For they gave according to their means, as I can testify, and beyond their means, of their own accord,  begging us earnestly for the favor of taking part in the relief of the saints—  and this, not as we expected, but they gave themselves first to the Lord and then by the will of God to us.
(2 Corinthians 8:1-5 ESV)
They gave what they could afford, and then they gave more!
With examples like this, I really struggle with the idea that giving %10 is sufficient. The example in Scripture is of generous, joyful, sacrificial giving. We cannot ignore the implications that this has for our lives. We should continually ask ourselves, “Can I give more? What else can I give away?” There should be nothing about our lives that resembles the love of money and possessions. When people see us, we want them to see Christ who generously gave everything to us. Let us follow that example.