Prayer avails for the salvation of others when every other means seems to fail. The disciples spent ten days in prayer. Then came Pentecost and a revival that brought thousands into the kingdom. John Livingstone, with a few friends, spent a whole night in prayer, and the next day five hundred persons gave themselves to Christ. Two sisters agreed to spend the night in prayer in behalf of an unconverted brother. That night, although twenty miles away, the young man tossed on his bed in agony of conviction, and next day started for home, and found salvation. Prayer is omnipotent; and, if we would see the kingdom of Christ come speedily in the world, we must have a great revival of prevailing prayer. STUDY XIII. FAITH. Memory Verse: "Verily, verily, I say unto you, He that believeth on me, the works that I do shall he do also; and greater works than these shall he do; because I go unto my Father."--(John xiv, 12.) Scripture for Meditation: Heb. xi. Not the mystery of faith, nor the philosophy of faith, does the soul-winner need to study; but the simplicity, the childlikeness of faith. To believe God implicitly is to have victorious faith. "I can do all things through Christ which strengtheneth me," said Paul; and everywhere in the Bible we find the clear teaching that "God and one make a majority." To realize this in one's own life is to live the victorious life. But perhaps we should distinguish between trust and saving faith. Trust gives the life to God; faith takes from God that which he has promised in his Word. Trust is continuous; faith is a definite act. "Faith is the giving substance to things hoped for, the evidence of things not seen." (Heb. xi, 1.) It is true that we walk by faith now; but faith has a clear eye. Faith can see the clouds full of chariots and horses. Faith can see legions of angels marshaling themselves for our defense. Faith can see that every promise of God is steadfast, and will surely be fulfilled, and can claim its fulfillment. "Faith, mighty faith, the promise sees, And looks to that alone; Laughs at impossibilities, And cries, 'It shall be done.'" Of Barnabas it is said, "He was a good man, and full of the Holy Ghost and of faith." The fullness of faith will make unbelief and moral darkness impossible in the soul, and will generate a triumphant confidence in God. To have faith is to have power; and the little child, as well as the grown man, may possess this power, and exercise it in winning souls for Jesus. A little girl who had bowed at the altar and given her heart to God, pulled the pastor's coat at the close of the service, and said, "Will you please pray for my mamma?" "Certainly," said the pastor. And the next evening the little girl brought her mother to the service. When the invitation was given, she took her hand and led her to the altar. That little girl's faith won her mother to Christ.