According to law, but he also wanted to insure that freedmen were not returned in error.
No, the proposed 1861 13th was already passed by Democrats in Congress and signed by Democrat President Buchanan.
Lincoln neither proposed, supported it in Congress, nor signed it.
Lincoln did not object, he said, because he didn't believe the proposed new amendment changed anything then understood, only made the words more explicit.
Lincoln may well have hoped the proposed new amendment would help voters in Upper South and Border States to vote against secession, and it did that.
But it was ratified by only four states and soon enough forgotten.
By sharp contrast, the 1865 13th Amendment abolishing slavery was indeed "fully supported" by Lincoln so passed Congress and was quickly ratified by enough states to become part of the US Constitution.
As for Lincoln's alleged "famous" quote about an "abolitionist brush", the "quote" is not famous enough to be found with an ordinary google search.
IIRC Lincoln brought WV into the mix to have another free state with two senators. I would appreciate your comments.
I read book abut the plan to assassinate Lincoln at the baltimore train station when he switched trains going to DC for his first inaugural. If southern sweated him dead then they must have had a reason and not seen his as supporting slavery.