Believers in Jesus, as we read in the Scriptures, are "all children of the light, and children of the day," and are privileged to "walk in the light, as God is the light," God Himself being "their everlasting light, and their God their glory." Thus "walking in the light," they "have fellowship one with another;" and more than this, "with the Father, and with His Son Jesus Christ." Abiding in this light and in this fellowship, their "joy is full," "out of weakness they are made strong," in all conditions of existence they find perfect content, and are "more than conquerors through Him that hath loved us," and "having all sufficiency for all things, are abundantly furnished for every good work." If all this is not true of any believer, it is because he is living below his revealed privileges, and is thus living because he does not "know the things which are freely given us of God." It contradicts every true idea of Christian character, to suppose that a true believer in Christ will "walk in darkness," knowing that he may "walk in the light;" will remain weak, knowing that he may be girded with "everlasting strength;" and will continue "carnal, sold under sin," knowing that he may enjoy "the glorious liberty of the sons of God." The specific and exclusive object of the following treatise is to make known to all who would know and understand their privileges as "the sons of God" and "believers in Jesus," the forms of divine knowledge above referred to. To the prayerful examination of all who are "walking in the light," or are inquiring after the light, the work is commended, with the fervent desire and prayer of the author, that "their joy may be full." ASA MAHAN (1799-1889) was America's foremost Christian educator, reformer, philosopher, and pastor. He was founding president of two colleges and one university, where he was able to inspire numerous reforms, publish authoritative philosophical texts, and promote powerful revivals like his close associate Charles Finney. He led the way on all important fronts while being severely persecuted. He introduced the new curriculum later adopted by Harvard, was the first to instruct and grant liberal college degrees to white and colored women, advised Lincoln during the Civil War, and among many other remarkable achievements, was a father to the early evangelical and holiness movements.