It goes to show
Definition 1 of 2
Pro Tip 1/3Emphasizing Lessons
Used when a situation teaches something informative or provides an example. 
He eventually won despite setbacks—it goes to show persistence pays off.
Pro Tip 2/3Affirming Beliefs
Confirms a belief or underscores a widely held idea or value. 
She donated anonymously; it goes to show her genuine generosity.
Pro Tip 3/3Unexpected Outcomes
Used when the outcome is different from what was anticipated, pointing out the lesson. 
The rookie scored the winning goal, it goes to show experience isn't everything.