Unable to find reference to that quote, if yo have it please provide.
Here is one place I found a similar statement. It isn't the one I remember seeing before, but perhaps it will do.
Testimony of Col. John B. Baldwin
" 'He [Lincoln] said something about the withdrawal of the troops from Sumter on the ground of military necessity. Said I, "that will never do under heaven. You have been President a month to-day, and if you intended to hold that position you ought to have strengthened it, so as to make it impregnable. To hold it in the present condition of force there is an invitation to assault. Go upon higher ground than that. The better ground than that is to make a concession of an asserted right in the interest of peace."-"Well," said he, "what about the revenue? What would I do about the collection of duties?" Said I, "Sir, how much do you expect to collect in a year?"-Said he, "Fifty or sixty millions." "Why sir," said I, "four times sixty is two hundred and forty. Say $250,000,000 would be the revenue of your term of the presidency; what is that but a drop in the bucket compared with the cost of such a war as we are threatened with? Let it all go, if necessary; but I do not believe that it will be necessary, because I believe that you can settle it on the basis I suggest." He said something or other about feeding the troops at Sumter. I told him that would not do. Said I, "You know perfectly well that the people of Charleston have been feeding them already. That is not what they are at. They are asserting a right. They will feed the troops and fight them while they are feeding them. They are after the assertion of a right. Now, the only way that you can manage them is to withdraw from them the means of making a blow until time for reflection, time for influence which can be brought to bear, can be gained, and settle the matter. If you do not take this course, if there is a gun fired at Sumter-I do not care on which side it is fired-the thing is gone." "Oh," said he, "sir, that is impossible."'"
Perhaps others, who likely do a better job than I do keeping up with where certain quotes are, can find a better source.