At a first time Jesus gives this commandment only to His disciples.But at that time they did not understand it. Through the death of cross and Pentecost they know Jesus`love and forgiveness of sin.Then by the force of holy Spirit They began to love one another.We cannot Love one anothe by our own self`s belief.To understand Jesus`commandment and to practise it will be realized by prayers of Private Rooms,I think.Please correct my opinion.