A Brief Definition:
"St. Thomas begins his treatise on charity [or love] by stating that it is friendship between God and man. Like every friendship, it implies a mutual love based on the communication of some good. Charity [or love] is a supernatural habit infused by God into the will, by which we love God for Himself above all things, and ourselves, and our neighbour for God.
The object of love is primarily God, secondarily ourselves and our fellow human beings. The object of love is God as supreme goodness in Himself and as our ultimate end. The love of God which is 'poured into our hearts through the Holy Spirit who has been given to us' (Rom 5:5) necessarily presupposes sanctifying grace. It makes us children of God and heirs of glory."
[Jordan Aumann, O.P., Spiritual Theology (Huntington, Indiana: Our Sunday Visitor, Inc., 1980) p.266]
A Brief Quotable Quote: Above all, do not be afraid of loving God. Do you not know that the more we love God, the happier we are? Because this is our ultimate end, the end for which we are all created. Do you not know that we are made to love God, so much so that outside of God there is nothing but emptiness?
[cf. Gabrielle Bosis, He and I (Sherbrooke, Quebec: Editions Paulines, 1985, p.221]