Every tithe of the land, whether of the seed of the land or of the fruit of the trees, is the LORD's; it is holy to the LORD. (Leviticus 27:30, ESV) Bring the full tithe into the storehouse, that there may be food in my house. And thereby put me to the test, says the LORD of hosts, if I will not open the windows of heaven for you and pour down for you a blessing until there is no more need. (Malachi 3:10, ESV) I have heard the about tithing from the above two portion a lot. Pastors especially in pentecostal churches bring it up before an offering is collected. There are times when a pastor may repeat it, especially during Christmas and New year services when the need is a lot and income is less. I have been to prosperity churches where they misuse these verses a lot, even in some cases where they make it like a ponzi scheme where you gain 10 dollars / pounds / euros or rupees for every 1 you give away and then there are accompanied testimonials from the riche...
....giving up all that inferior stuff so I could know Christ personally