THE VIRTUE OF LOVE
LOVE OF GOD: The supreme Christian virtue, it is the virtue that informs and animates all Christian actions. Love of God can be an explicit and formal sort of action, or it can be the motive which underlies and animates all other Christian actions and thus perfects them. The command to love God without restriction is at the heart of Old Testament teachings, and the sort of love that is due to God is what is to be given to one's neighbor. The love of God which the Christian is to manifest to God is to be of the same character and intensity as that with which God has loved us.
Our capacity to love God ultimately derives from God's love for us, which is best exemplified in the Passion and death of Jesus for the sins of all humanity. God loves us as Creator and Redeemer, and His love for us is the motive for His creation, while we love Him as created beings and from our debt to Him. Love of God that mirrors His love of us makes perfect love of neighbor possible as it sets the terms for this love. Because God loves us unreservedly and without restriction, He can demand this sort of love in return, and that it be expressed to our neighbor as well. God loves humanity universally as His special creation, and because His love is universal, He can demand this love of humanity by imparting His Spirit on it to make this possible.
LOVE OF NEIGHBOR: Catholic belief holds that it is a sin not to show love to all, even to enemies. It demands that unlimited love for all persons be shown, not only that those close to one be loved, but those afar, and it requires that Christians love not only their friends and those who do good for them, but also that enemies and those who do them harm be loved as well. This form of love is the sign par excellence of the Christian contradiction of the world with its hatred, selfishness and egotism.
Love of neighbor is the source of the unity of the Church and the clearest sign of the presence of the Holy Spirit, for the Holy Spirit is the source of charity. True love of neighbor reveals God's love for us, is faithful, unselfish and a source of peace. Love of neighbor is grounded in the Eucharist and derives from it, for the love shown in the Sacrament is the model for love of neighbor. In loving one's neighbor, one formally encounters Christ, Who also loves the neighbor, causing a believer to love the neighbor as Jesus does.