Whereas love for God is the source and starting point of every virtue, love for the world is the cause of all evil. For that reason these two loves are at enmity with each another and destroy each other. As the Lord's brother declares: "Friendship of the world is enmity to God. Whosoever therefore will be a friend of the world is the enemy of God" (Jas. 4:4). And John, whom Christ loved, says, "If any man love the world, the love of the Father is not in him. For all that is in the world, the lust of the flesh, and the pride of life, is not of the Father" (cf. 1 John 2: 15-16). Let us take heed, brethren, lest by loving evil desires and being arrogant to one another, we fall away from our heavenly Father's love. For these two evils include every passion which separates us from God.
The foundation, origin and cause of these two opposing roots, love for God and love for the world, is another pair of implacably opposed loves. Love for the world springs from love for the body, since we love the world because of our body's well-being. On the other hand, love for God comes from love for our spirit, our soul, for we love God on account of the comfort and good fortune our souls will have in the world to come. The great Paul bears witness to the fact that these two attitudes are at enmity with each other by saying, "The flesh lusteth against the Spirit", meaning the soul, "and the Spirit against the flesh" (Gal. 5: 17).
How does love for our own soul engender love for God? We are threatened with the unquenchable fire of hell and promised God's eternal kingdom. This everlasting kingdom is for those who listen to God's commandments and act upon them, whereas hell-fire is for those who by their actions disobey Christ's Gospel. When true believers, who love their souls and desire to keep them for eternal life, hear these threats and promises, they immediately conceive longing and fear, fear of the unending pain in the threatened fire of hell, and longing for the promised kingdom of God with its eternal joy.
Because they yearn to attain to divine, unfading delight and are afraid of suffering in that fire, they break their ties with everything passionate, blameworthy and earthly, and strive to cleave to God through intense prayer, knowing for sure that He alone has power and authority to deliver them from the agony of hell, and make them worthy of that eternal joy which passes understanding. In this way they acquire love for God, and as they become more perfectly united with God through this love, they gain all the virtues as well. When God is at work in us, every kind of virtue becomes our own, but when He is not, everything we do is sin. As the Lord says in the Gospel, "Without me ye can do nothing" (John 15:5). Those who truly act virtuously are aware of this, and do not pride themselves on any of their achievements, but humbly glorify God, the Fount of virtues, by Whom they are filled with the light that bestows goodness. When the air is full of sunlight, the glory and radiance it displays are not its own but the sun's. So those who are united with God through fulfilling His commandments are, according to Paul, the sweet savour of Christ (cf. 2 Cor. 2:15). They have Christ's fragrance, and proclaim the virtues of Him Who called them "out of darkness into His marvellous light" (1 Pet. 2:9).
Homilies of St. Gregory Palamas, Volume Two, St. Tihkon's Seminary Press
The entire Homily is posted here: St. Gregory Palamas - On Virtues and Their Opposite Passions