Our Scripture reading today is Deuteronomy 10:12-13.
Verse 13, "To keep the commandments of the LORD,"
Our obedience to the LORD will always lead to our good and His glory.  The song says that obedience is still the best way we show that we believe.  Our behaviour as Christians speaks very loudly to whether or not we truly believe what we say we believe.  
The commandments of the Lord are not meant to be a burden.  1 John 5:3 says, "For this is the love of God, that we keep his commandments: and his commandments are not grievous."  The love God has for His children is proven in His commandments.  They keep us from the destruction that the devil has planned.  Where would we be without our loving Lord?