Abraham Lincoln viewed slavery as morally unjust and wrong from the beginning of his life. Abraham Lincoln worked alongside abolitionists to improve Black lives and abolish slavery.  In a three hour speech in 1854, Abraham Lincoln admonished slavery and opposed it legally, socially, and economically.  Lincoln avidly opposed slavery for the entirety of his life and took measured steps throughout his time as a lawyer and President to work with abolitionists against the institution of slavery. 
Abraham Lincoln did not seek to end slavery during his term as President. Abraham Lincoln did not wish to alter the Constitution, which sanctioned slavery.