Abraham Lincoln tried to get the approval of the border states with the Emancipation Proclamation by making it clear that the proclamation applied only to the Confederate states that were in rebellion, and not to the border states that remained loyal to the Union.
Lincoln knew that the border states were crucial to the Union's war effort and that any move that would alienate them could be disastrous. By exempting the border states from the Emancipation Proclamation, Lincoln hoped to avoid causing further divisions among the states and to maintain their support for the Union cause.
Additionally, Lincoln offered a plan of compensated emancipation to the border states, which would have provided financial compensation to slave owners who voluntarily freed their slaves. Although this proposal was not widely accepted, it demonstrated Lincoln's willingness to work with the border states and his efforts to keep them on the side of the Union.