When the Lord Jesus is pleased in some solemn hour to reveal himself to our soul, when he graciously condescends to take the veil from off our heart that we may behold his glory, the glory as of the only begotten of the Father, full of grace and truth, when he kindly favours us with some manifestation and discovery of himself as the Son of God, the brightness of the Father's glory and the express image of his Person, then we know that the Son of God is come. How do you know that the sun rose this morning? By the light which rose with it.
So we may say, spiritually, "How do you know that the Son of God is come?" By the Sun of righteousness arising upon you with healing in his wings and the shining light which he diffuses in your heart. So the Lord speaks to Zion: "Arise, shine, for thy light is come, and the glory of the Lord is risen upon thee." That is the way in which the darkness is dispersed; for he adds, "Behold, the darkness shall cover the earth, and gross darkness the people; but the Lord shall rise upon thee, and his glory shall be seen upon thee."
Did not our blessed Lord say, "I am come a light into the world, that whosoever believeth on me should not abide in darkness?" And has he not promised, "He that followeth me shall not walk in darkness, but shall have the light of life?" Now as God is light, when he is pleased to shine into the soul, we walk in the light as he is in the light, and then we have fellowship with one another, and the blood of Jesus Christ cleanseth us from all sin. This is the best, this is the surest, this is the safest way to know that the Son of God is come.
We know also that the Son of God is come by his presence; by his power put forth on our behalf; by the answers which he gives to prayer; by the way in which he appears in dark and gloomy hours, making crooked things straight and rough places plain, discovering himself to us as the Way, the Truth, and the Life, shewing unto us that in him there is rest and peace, solid, abiding happiness, and in no other. He thus draws and fixes our eyes upon himself, where he sits at the right hand of the Father in the fulness of his grace, glory, and majesty. Thus we know that the Son of God is come. Every prayer, every petition, every sigh and cry, every longing look that you cast up to him, and every word of his grace, every sweet promise, every glimpse or glance of the King in his beauty, which you receive out of his fulness, are all so many testimonies that the Son of God is come, and that you know that he is come.