In conflict with Satan, whether in our own experience or in the attempt to rescue souls from his accursed thrall, there is no weapon so useful as the Spirit's sword, which is the Word of God. Our blessed Lord parried the devil's attacks by "It is written"; and we shall not improve on his method. The armour of the enemy is impenetrable to all blades save that which has been forged in the celestial fires of the Holy Spirit.
And if you would acquire the habit of intercessory and earnest prayer, so as to be able to watch thereunto, and to persevere, pouring out supplications and entreaties for all saints, you can only do so "in the Spirit." He alone can teach this holy art, or give this eager temper of soul, or perpetuate its practice. Let us earnestly seek it at his hand; for there is nothing that so refines or ennobles, purifies or strengthens the spirit, as this constant breathing out of prayer and breathing in of the fulness of God.