As unknown, and yet well known,.... Not unknown to Father, Son, and Spirit, or to one another, but to the world; and that not with respect to their outward estate, but their spiritual and eternal state; as that they were the chosen of God, the children of God, and born again; they knew not what a life they lived, or what they lived upon; and as they were unacquainted with their inward troubles, they were strangers to their spiritual joys here, and to what they shall partake of hereafter.
Moreover, something more may be intended in this word "unknown"; as that they were not owned, esteemed, and approved of by them, but slighted, despised, hated, and persecuted:and yet well known; to God the Father, who loved them with an everlasting love, chose them in Christ, gave them to him, made a covenant with him on their account, and sent his Son to redeem them, which knowledge of them is special, eternal, affectionate, approbative, and attended with care of them; well known to Jesus Christ, who knows all that are his, specially, distinctly, perfectly, and that from everlasting, bears a strong affection for them, takes great care of them, indulges them with intimate communion with him, and openly owns and acknowledges them as his own; well known to the Spirit of God, who enlightened and quickened them, regenerated and sanctified them, wrought faith and every other grace in them, witnessed their adoption to them, led them into all truth, filled and furnished them with his gifts, and dwelt in them, and abode with them, as the seal and earnest of their future glory; and were well known to the saints, and one another: they loved each other, delighted in each other's company; they knew each other's experiences, joys, and sorrows, and, in some measure, their hearts, and even their spiritual and eternal estate.
As dying, and behold we live. They were as dying men, having the seeds of mortality in them, being subject to diseases, which bring on death; and especially as they carried about with them the dying of the Lord Jesus, were continually exposed to death, and in danger of it, lived in the views of it, had the sentence of it in themselves, and were appointed to it.
And "behold", to admiration "we live"; a natural life, which we have from God, depends upon hint, and is preserved by him amidst a thousand dangers and enemies to which it is exposed; and we live a spiritual life, a life of grace from Christ, a life of faith on him, and communion with him.