Sincere faith is not displayed, it is proven.
Generate an image in your mind of yourself in front of a full-length mirror. All carbon-based material is removed from your body, clothing, skin, every ounce of flesh and bone; only your soul remains. How do you look? Pretty spiritual?
A screen slowly lowers from above, inserting itself between you and your reflection. The image is distorted as it is filtered through this screen and its Litmus test of sincerity, answering these questions in pure honesty:
Do you practice what you preach?
Are you content with the approval of God or do you want approval from men?
Are you driven by gaining power over others?
Do you strive to serve others of are you focused on yourself?
Are you keeping others from knowing Jesus?
Are you focused on the things that really matter?
Are you focused on outward appearances instead of inward reality?
Take another look in that mirror through the exposing eyes of this filter. Does your faith still look as sincere as you thought?
Until we are able to see the cross as something done by us, we will never see it as something done for us.
Sincere faith cannot be displayed, it must be evident.