The gospel rightly understood, taught, received, felt and practised, is anti-slavery as it is anti-sin.

Just so far and so fast as the true spirit of the gospel obtains in the land, and especially in the lives of the oppressed, will the spirit of slavery sicken and become powerless like the serpent with his head pressed beneath the fresh leaves of the prickly ash of the forest.
There is not a solitary decree of the immaculate God that has been concerned in the ordination of slavery, nor does any possible development of his holy will sanctify it.
He has permitted us to be enslaved according to the invention of wicked men, instigated by the devil, with intention to bring good out of the evil, but He does not, He cannot approve of it.

He has no need to approve of it, even on account of the good which He will bring out of it, for He could have brought about that very good in some other way.
God is never straitened; He is never at a loss for means to work.

Could He not have made this a great and wealthy nation without making its riches to consist in our blood, bones, and souls?
And could He not also have given the gospel to us without making us slaves?
My friends, let us then, in our afflictions, embrace and hold fast the gospel.

The gospel is the fulness of God.