I quit tithing years ago. Started giving quite a bit less than a tenth. Within a couple of months, I received the biggest raise, both in dollars and as a percentage increase, in my entire career. And that was around the time somebody stood up in a testimony service and (among other things) said "God can't bless you if you're not tithing".
This year, after not giving much to church at all for the last several years (I give to cancer research and many other such charities, but not 10% of my income), I got no raise at all! Think it's because of my "unfaithfulness"?
We just sold our previous house, after almost two years of trying. Would it have sold quicker if we were tithers? How much quicker?
Every story of God's blessing because of faith is balanced with counterexamples. The rain (blessings) falls on the just and the unjust.
Faith works! Sometimes! Faith also fails, sometimes. When it "works", folks like to talk about it, and people remember it. When it doesn't, it's chalked up to God's better wisdom in the matter, or it just isn't noticed or quickly forgotten.
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Hebrews 13:23 Know ye that our brother Timothy is set at liberty