None of us are exempt from stumbling. But we should never become complacent or make excuses for our stumbling. God's word has much to say concerning what life looks like when we follow after Christ and how that life prevents us from stumbling. 
A heart of humility and one that hungers and thirsts for His righteousness will keep us walking in the light where we are promised to never stumble. Scripture tells us that Jesus is the light of the world and if we walk in the light of His presence we will never stumble in the darkness. 
We are told that if we hate our brother, then we no longer walk in the light but will stumble in the darkness. We can't say we love God then hate our brother.
Jesus told Peter that he was a stumbling block to Him for he had his mind set on earthly interest instead of God's interest. How many times have we been like Peter; a stumbling block to God because our hearts were set on our own interest and not God's?
How many times have we become stumbling blocks to our family, friends, neighbors, or co-workers because of our selfishness and self-righteous behavior?
Our everyday relationship with Jesus Christ must take precedence before anything else. God's word tells us that we need to make the most of every opportunity because the day is evil. There are enough stumbling blocks in the world today; we do not need to add our lives to that list.