The basic cause of Milton's lament is that he has always been a student, a reader and a writer, a literary man. Now that he is blind, he is unable to engage in the literary work which has given his entire life meaning. This would obviously be a terrible blow to a man of Milton's genius and dedication. What is impressive about the sonnet is the tone of patience which prevails throughout and which is summated in that final beautiful line of iambic pentameter: "They also serve who only stand and wait." He is not expressing frustration but patience, humility, and acceptance of the will of God. This is perhaps one of the most serious sonnets ever composed. It deals with an issue with which the reader can easily sympathize. How terrible it must be to be blind and unable to do the one thing you feel created to do! It is like Beethoven becoming totally deaf when his whole life was dedicated to his music and he was the foremost musical genius of his age. What Milton means by
though my soul more bent
To serve therewith my Maker, and present
My true account...
is simply that he would like to be able to continue to exercise his great literary genius ("that one talent which is death to hide"). His soul is undoubtedly "more bent" to do so because, being blind, there is nothing else for him to do but sit and think thoughts he would like to be able to put down on paper and share with others. When something really tragic happens in one's personal life, it is natural to question, "Why does this have to happen to me?" Being a deeply religious man, Milton wonders why God would have given him the "one talent" and then denied him the power to use it. He does not allow his condition to weaken his religious faith.