Of all the commandments of God, Jesus’s “Great Commandment” is perhaps the most challenging of all, for it requires of us two difficult things. We might rightly be challenged with the idea of loving others, and we may spend a great deal of effort trying to figure out what that means, what that looks like on a practical level. But first we must reflect on our own experience of God’s love for us, our experience of His goodness, mercy, and generosity, and then we will know exactly how to love others. It may perhaps, then, be helpful to learn from one of the Church’s great Doctors, St. Thérèse of Lisieux, reading what she has written in her autobiography on precisely this commandment:
“Now Jesus made known to me His Will at the Last Supper, when He gave His Apostles His New Commandment: "Love one another as I have loved you" (John 13:34). I set to work to discover how Jesus had loved them. I found that He had not loved them for their natural qualities, for they were ignorant and taken up with earthly things, yet he called them His friends (John 15:15) and His brothers (John 20:17) and wanted to have them with Him in His Father's Kingdom; He was ready to die on the Cross to make this possible, saying: "Greater love than this no man hath, that a man lay down his life for his friends" (John 15:13).
Meditating on these divine words, I saw only too well how very imperfect was my love for my Sisters; I did not really love them as Jesus loves them.
I see now that true charity consists in bearing with the faults of those about us, never being surprised at their weaknesses, but edified at the least sign of virtue . . . Under the Old Law, when God told His people that they must love their neighbor as themselves, it was before He had come upon earth Himself, knowing how much man loved himself, it was the best He could ask. But when Jesus gives His Apostles a New Commandment (John 13:34), His own Commandment (John 15:12), He asks them to love one another, not only as they love themselves, but as He Himself loves them and will love them even unto the consummation of the world!”