Growth Mindset, not Fixed Mindset
A 'Growth Mindset' is the first step towards success in mathematics. (For more info refer to Mindset: The New Psychology of Success, Carol Dweck and Mathematical Mindsets: Unleashing Students Potential through Creative Math, Inspiring Messages and Innovative Teaching, Jo Boaler).
If I want my students to have a growth mindset, I can't be teaching them with a fixed mindset. I am open to different ways of looking at a problem and encourage my students to think of various strategies to solve a given problem. Knowledge can be inhibiting sometimes, but it should not stop you from being creative and curious.