Some things are so plain and observable that the bearer of such news often earns the moniker "Captain Obvious." That is especially true if siblings are involved. 

The Apostle Paul doesn't quite use that terminology in the first chapter of Romans but he does remind us that some spiritual truths should be obvious to the average soul. God is in plain sight when you simply observe His creation. In fact, you have to deny the obvious to convince yourself that He is not there. 

"Because that which may be known of God is manifest in them; for God hath shewed it unto them.  For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse:  Because that, when they knew God, they glorified him not as God, neither were thankful; but became vain in their imaginations, and their foolish heart was darkened. Professing themselves to be wise, they became fools," Romans 1:19-22.