I cannot show you something that does not exist. There is no passage in the New Testament where Christians are taught to submit tithes. The complete absence of such is instructive.
There are, however, many passages where Christians are taught how to give.
Again, because "tithing" is of the Mosaic Law, and Christians are not under the Mosaic Law, there should be no need for particular instruction, any more than there need be specific instruction not to stone adulterers, attend the Temple thrice a year, bring grain offerings, have your mouldy house inspected, or get the priest to tell you that your eczema has settled down and you can come to worship again.
Why would God waste all that space telling us that specific ordinances of the Law are no longer in effect? Why is His word insufficient when it says Christians aren't under the Law?