"He who sacrifices freedom for security..." If you give up your freedom for security you lose you right to chose, and that your security may be compromised. Hence "...deserves neither and will lose both." When it says "...deserves neither..." it means, any man who chooses safety over freedom is not deserving of security, nor freedom, because every man has fought hard for freedom and to give it up willingly for safety is cowardice.
Hope this helps.