This is from the blog The Voice of One:

John Milton was a Christian and poet in the 1600’s.  By age 44, he went blind.  Milton wondered if he could continue serving God without eyesight.  Sometimes, he simply felt useless.

Milton’s anxiety and grief spill out in his 19th sonnet: “When I consider how my light is spent.”  The sonnet ends with the Lord’s wonderful ministry and comfort–

When I consider how my light is spent,
   Ere half my days, in this dark world and wide,
   And that one Talent which is death to hide
   Lodged with me useless, though my Soul more bent
To serve therewith my Maker, and present
   My true account, lest he returning chide;
   “Doth God exact day-labour, light denied?”
   I fondly ask. But patience, to prevent
That murmur, soon replies, “God doth not need
   Either man’s work or his own gifts; who best
   Bear his mild yoke, they serve him best. His state
Is Kingly. Thousands at his bidding speed
   And post o’er Land and Ocean without rest:
   They also serve who only stand and wait.”
I have mentioned I’m in a season of rest.  At least, I think that’s what it is.  I know I’m not doing much in the way of study, projects, or anything else.  Sometimes, I just feel like I’m wasting my life.
On days when I feel like a broken, failed person, Milton’s words come back to me: “who best Bear his mild yoke, they serve him best. […]  They also serve who only stand and wait.”  I love this image.  In any court there are those coming and going.  But there are also those who stand waiting for the king’s order.  Activity is only useful if the king requests it.  To busy oneself without the king’s command is not to serve Him but self.
So it is with the King of kings.  I am not my own.  I am His.  I wait for His Spirit to rouse me to action.  ‘Til then, I stand, I wait, I listen for His word.
This reminds me of another who sat listening to Jesus: Mary of Bethany.  When Mary’s busy sister scolded her for not busying herself to serve Jesus, the Lord replied, “Martha, Martha, you are worried and upset about many things, but one thing is necessary. Mary has chosen what is better and it will not be taken away from her” (Luke 10:41).
In this season, I hope to know Jesus more: the one who is necessary, the one who is better than busy-ness.  My prayer is that I value Him more than serving Him.   
The Three Hermits