How Lincoln felt about Jefferson seems to be a bit unclear on first glance. On the one hand, Lincoln's law partner William Henry Herndon claimed that Lincoln:
hated Thomas Jefferson as a man - rather as a politician, and yet the highest compliment I ever heard or read of his was paid to the memory of Jefferson.
On the other hand, the compliment Herndon mentions can be found in Lincoln's letter to Henry L. Pierce:
Springfield, Ills, April 6, 1859
Messrs. Henry L. Pierce, & others.
Gentlemen
Your kind note inviting me to attend a Festival in Boston, on the 13th. Inst. in honor of the birth-day of Thomas Jefferson, was duly received. My engagements are such that I can not attend.
Bearing in mind that about seventy years ago, two great political parties were first formed in this country, that Thomas Jefferson was the head of one of them, and Boston the head-quarters of the other, it is both curious and interesting that those supposed to descend politically from the party opposed to Jefferson should now be celebrating his birthday in their own original seat of empire, while those claiming political descent from him have nearly ceased to breathe his name everywhere.
Remembering too, that the Jefferson party were formed upon its supposed superior devotion to the personal rights of men, holding the rights of property to be secondary only, and greatly inferior, and then assuming that the so-called democracy of to-day, are the Jefferson, and their opponents, the anti-Jefferson parties, it will be equally interesting to note how completely the two have changed hands as to the principle upon which they were originally supposed to be divided.
The democracy of to-day hold the liberty of one man to be absolutely nothing, when in conflict with another man's right of property. Republicans, on the contrary, are for both the man and the dollar; but in cases of conflict, the man before the dollar.
I remember once being much amused at seeing two partially intoxicated men engage in a fight with their great-coats on, which fight, after a long, and rather harmless contest, ended in each having fought himself out of his own coat, and into that of the other. If the two leading parties of this day are really identical with the two in the days of Jefferson and Adams, they have perfomed the same feat as the two drunken men.
But soberly, it is now no child's play to save the principles of Jefferson from total overthrow in this nation.
One would start with great confidence that he could convince any sane child that the simpler propositions of Euclid are true; but, nevertheless, he would fail, utterly, with one who should deny the definitions and axioms. The principles of Jefferson are the definitions and axioms of free society.
And yet they are denied and evaded, with no small show of success.
One dashingly calls them "glittering generalities"; another bluntly calls them "self evident lies"; and still others insidiously argue that they apply only to "superior races."
These expressions, differing in form, are identical in object and effect--the supplanting the principles of free government, and restoring those of classification, caste, and legitimacy. They would delight a convocation of crowned heads, plotting against the people. They are the van-guard--the miners, and sappers--of returning despotism.
We must repulse them, or they will subjugate us.
This is a world of compensations; and he who would be no slave, must consent to have no slave. Those who deny freedom to others, deserve it not for themselves; and, under a just God, can not long retain it.
All honor to Jefferson--to the man who, in the concrete pressure of a struggle for national independence by a single people, had the coolness, forecast, and capacity to introduce into a merely revolutionary document, an abstract truth, applicable to all men and all times, and so to embalm it there, that to-day, and in all coming days, it shall be a rebuke and a stumbling-block to the very harbingers of re-appearing tyranny and oppression.
Your obedient Servant A. Lincoln--
It's tempting to say that Lincoln was just exaggerating rhetorically here, but this is indeed the highest compliment we have from Lincoln towards anyone. My feeling is that Lincoln felt towards Jefferson in a similar way as most Americans do today; Lincoln was critical of aspects of Jefferson's life, such as Jefferson's involvement with slavery, but nonetheless admired the man as a great visionary and a prophet of equality. As the "Dean of Lincoln Studies," Richard N. Current pointed out, Lincoln revered the Declaration of Independence. The 16th President even commented that he had "never had a feeling politically that did not spring from the sentiments embodied in the Declaration of Independence." The evidence of Lincoln's genuine admiration for Jefferson and his creation can be seen even in Lincoln's most famous speech, the Gettysburg Address:
Four score and seven years ago our fathers brought forth, on this continent, a new nation, conceived in Liberty, and dedicated to the proposition that all men are created equal.
Now we are engaged in a great civil war, testing whether that nation, or any nation so conceived, and so dedicated, can long endure. We are met on a great battlefield of that war. We have come to dedicate a portion of that field, as a final resting-place for those who here gave their lives, that that nation might live. It is altogether fitting and proper that we should do this.
But in a larger sense, we can not dedicate — we can not consecrate — we can not hallow — this ground. The world will little note, nor long remember what we say here, but it can never forget what they did here. It is for us the living, rather, to be dedicated here to the unfinished work which they who fought here have thus far so nobly advanced. It is rather for us to be here dedicated to the great task remaining before us — that from these honored dead we take increased devotion to that cause for which they here gave the last full measure of devotion — that we here highly resolve that these dead not have died in vain — that this nation, under God, shall have a new birth of freedom — and that government of the people, by the people, for the people, shall not perish from the earth.
Some historians, such as Allen C. Guelzo, have argued for a Lincoln critical of Jefferson, but the vast majority of scholars tend to look at Lincoln as a man who sincerely believed in Jefferson and in his cause in an almost religious sense, as providential as could be had with Lincoln's "Calvinized Deism". That the amateur geometrist Lincoln referred to Jefferson's ideas as "the definitions and axioms of a free society" is high praise indeed, and these ideas from the Declaration of Independence were as foundational to Lincoln's thought as Euclid's axioms were to mathematics.