Borrowed money-neither income nor asset
You write: "i believe we should pay tithe on any money that comes to us even if borrowed." May I ask: How did you come to that conclusion?
Borrowed money is neither income nor asset. We are not required to pay income tax on borrowed money because it is not income. It is not an asset because it does not increase our net worth. Instead, it is a liability. The reason it is a liability is that we have to PAY IT BACK. The fact is we are not required to pay tithes on our liabilities.
Grace to you,
Bible Answer: There is no scriptural precedent for paying tithes in the New Covenant. The ten percent tithe of the Old Covenant was for the Levites. The other eleven tribes were given inheritances of land when they came into Israel, but the Levites, who were in service to the tabernacle and had no inheritance of land, were given the sacrifices and tithes as their inheritance instead. (Num 18:20-24) This was the point in the prophets when God was angry that the people were robbing him. There was no meat in his house, and thus the promised inheritance to the Levites was not being properly managed. (Malachi 3:8-10)
A lack of "tithing" commandments in the New Testament doesn't release us from the good work. Jesus commanded us to love one another as he loved us. (John 13:34-35)
Charity is most definitely a good thing, and also at the top of the list of progression (2 Pet 1:3-11); "add to brotherly kindness charity."
However, there are no set directives on the amount, frequency, or establishment to which these charitable contributions are to be made.
We are told that a laboror is worthy of his wages (1 Tim 5:18), so it is reasonable, and also a good thing, to tithe to whatever church you frequent in order that the pastor might receive a fair wage if he is providing sound spiritual instruction, and not suspicious of material gain.
The "ten percent" was a matter of the Old Covenant. We are no longer subject to the Old Covenant but the New Covenant. The New Covenant instructs us to give as we purpose in our hearts, and that not grudgingly. Give cheerfully (2 Cor 9:6-8).
I would recommend giving to your church if they are good stewards of the funds (I would be wary of giving to churches that are excessively lavish without good cause).
On the other hand, there are a lot of reliable charities out there that are worth giving to. The Red Cross being one of them... They help in any number of crises, and they have shown themselves good stewards time and again.
It is all really up to the individual. In 1 Corinthians 16:1-4, Paul gives instuction to take up the collection on the first day of the week, but this was a "collection for the saints" that would then in turn be distributed as needed during a famine that was prophesied and came to pass during the reign of Claudius Ceasar. (Acts 11:27-30)
Aside from a few examples of an organized collection, established as temporary relief for an upcoming famine, there is really nothing to suggest a tithe of any sort.
We should give to those in need. Faith without works is dead. (James 2:14-20) We need to love not in word, but in deed. (1 John 3:17-18) If we don't give when it is needed, then we are not really Christians.
But if we don't tithe to a church that costs as much as fifty nice houses, run by a pastor that teaches slack or incomplete lessons and drives home in an 80K vehicle after ignoring your opinion without a hint of consideration ... I don't think God would give to them either.
So, in short, you are not "required" to pay a tithe on borrowed money. Nor are you "required" to pay a tithe on earned money. The requirement was a requirement under the Old Testament Law. We are no longer under the law, and we can never be found righteous by it. (Galatians 3:10-29) But if anyone has a need, and you can fulfill it, it is sin to you if you know any good thing and do it not. Your money is your own. Spend it as you will, for it is the gift of God, but love your neighbor as yourself and give to those in need when and where you are able.