SIR,--I regret that you do not appreciate what I have repeatedly said to you in regard to the proper police arrangements connected with your household and your own personal safety. _You are in danger._ I have nothing to ask, and I flatter myself that you will at least believe that I am honest. If, however, you have been impressed differently, do me and the country the justice to dispose at once of all suspected officers, and accept my resignation of the marshalship, which is hereby tendered. I will give you further reasons which have impelled me to this course. To-night, as you have done on several previous occasions, you went unattended to the theatre. When I say unattended, I mean that you went alone with Charles Sumner and a foreign minister, neither of whom could defend himself against an assault from any able-bodied woman in this city. And you know, or ought to know, that your life is sought after, and will be taken unless you and your friends are cautious; for you have many enemies within our lines. You certainly know that I have provided men at your mansion to perform all necessary police duty, and I am always ready myself to perform any duty that will properly conduce to your interest or your safety. God knows that I am unselfish in this matter; and I do think that I have played low comedy long enough, and at my time of life I think I ought at least to attempt to play star engagements. I have the honor to be Your obedient servant, WARD H. LAMON. Mr. Lincoln had in his great heart no place for uncharitableness or suspicion; which accounts for his singular indifference to the numberless cautions so earnestly and persistently pressed upon him by friends who knew the danger to which he was hourly exposed. He had a sublime faith in human nature; and in that faith he lived until the fatal moment when the nations of the earth were startled by a tragedy whose mournful consequences no man can measure.