To speak of love is to dare to speak of God; for, according to St John the Theologian, ‘God is love; and he who dwells in love dwells in God’ (1 John 4:16)….’You shall love the Lord your God with all your heart, and with all your soul, and with all your might’ (Deuteronomy 6:5)….’with all your soul’ means with the intelligent, incensive and desiring powers of the soul, because it is of these three powers that the soul is composed. Thus the intellect should think at all times about divine matters, while the desire should long constantly and entirely, as the Law says, for God alone and never for anything else; and the incensive power should actively oppose only what obstructs this longing, and nothing else….
~St Peter of Damaskos
Prayerful Life 