In the third commandment we see the Lord state again that He is ‘the Lord your God’.  We are in covenant with Him, we know Him and His name.  So His name, which is a declaration of His character and nature, is spoken with a deep awareness of His presence and power.  We do not treat His name as though it is empty or without weight, but our aim is to honor the Lord’s name and treat it with the honor and glory that it’s due.