The phrase "show of support" means to publicly demonstrate or express one's approval, encouragement, or solidarity towards someone or a cause. Full definition
So I thank you again for your early show of support for this book. (steynonline.com)
To be clear, we raised nearly $ 800,000 via backers and investors; it's an impressive showing of support from our community and for our brand. (shacknews.com)
No dealer or collector has made a public show of supporting the market for abstract paintings. (artmarketmonitor.com)