I think "When I Consider How My Light is Spent" is a wonderful, poignant sonnet in which the poet explores his own grief over his blindness and expresses his fear that it will mean that he will be unable to use his abilities as he had hoped he would be able to. However, and this is the important part of the poem, he finds immense consolation in the idea that patient endurance of his limitations and trying to wait to see how he can serve God's will are just as important as being successful in the exploits of which he had dreamed. Note what the poem says:
"God doth not need
Either man's work or His own gifts. Who best
Bear His mild yoke, they serve Him best."
The enduring message about blindness seems to be that it does not prevent us from serving God, and that no matter what state we find ourselves in, whether blind or subject to some other limitation, what God wants us to do is to learn to "Bear His mild yoke" and wait and serve him patiently in the situation that we find ourselves. As much of a tragedy as Milton's blindness was, this poem is testament to the way that blindness does not make us less of a person to ourselves or to God.
In this sonnet the message is to show inner conflict of a man who had promised to do a great task but unfortunately when the time comes he is collided with the desister,making him complete blind at the age of forty five.He is a deeply religious man and it shakes his faith in Providence so much that unrest erupt into his innerself.But it is soon resolved that every man should bow before the Will of God.The sonnet thus is the picture of a crisis faced by a Milton,a sublime person bent upon the service of mankind.He is of the opinion that it is the gift of God and it is duty to make the best use of it.God does not worry of our worships because his state is kingly,thousands at his decree and pass over land and ocean without rest.The resultof it is the balance that the poet finds in the faith in God.
Whatever God does is for the best and thus no great disaster is
really a disaster but a manifestation of God`s mercy.Hence we should not lose the spirit but we should carry on to serve God.By service man is known as well as love to his Lord is known.