There is no more fatal blunderer than he who consumes the greater part of his life getting his living.
 Henry David Thoreau, Life Without Principle (1863). copy citation

Context

“If I should sell both my forenoons and afternoons to society, as most appear to do, I am sure, that, for me, there would be nothing left worth living for. I trust that I shall never thus sell my birthright for a mess of pottage. I wish to suggest that a man may be very industrious, and yet not spend his time well. There is no more fatal blunderer than he who consumes the greater part of his life getting his living. All great enterprises are ​self-supporting. The poet, for instance, must sustain his body by his poetry, as a steam planing-mill feeds its boilers with the shavings it makes. You must get your living by loving.” source