Quote 40
Dark and terrible as is this picture, I hold it to be strictly true of the overwhelming mass of professed Christians in America. They strain at a gnat, and swallow a camel. (Appendix.4)
One of the ways Douglass shows himself to be a true Christian (while slaveholders are not) is by quoting the Bible. The part about the gnat and camel comes from Matthew 23:24, where Jesus is rebuking the Pharisees for their hypocrisy.
Quote 41
I may be deemed superstitious, and even egotistical, in regarding this event as a special interposition of divine Providence in my favor. But I should be false to the earliest sentiments of my soul, if I suppressed the opinion. I prefer to be true to myself, even at the hazard of incurring the ridicule of others, rather than to be false, and incur my own abhorrence. From my earliest recollection, I date the entertainment of a deep conviction that slavery would not always be able to hold me within its foul embrace; and in the darkest hours of my career in slavery, this living word of faith and spirit of hope departed not from me, but remained like ministering angels to cheer me through the gloom. This good spirit was from God, and to him I offer thanksgiving and praise." (5.12)
Douglass has a high opinion of himself, and he knows that if he tells us that he always believed it was his destiny to be free, we might think he's a little arrogant or even crazy. But he tells us anyway, which shows us something important about him: he believes in the saying "To thine own self be true." And maybe he's right!
Quote 42
The holidays are part and parcel of the gross fraud, wrong, and inhumanity of slavery. They are professedly a custom established by the benevolence of the slaveholders; but I undertake to say, it is the result of selfishness, and one of the grossest frauds committed upon the down-trodden slave. They do not give the slaves this time because they would not like to have their work during its continuance, but because they know it would be unsafe to deprive them of it. This will be seen by the fact, that the slaveholders like to have their slaves spend those days just in such a manner as to make them as glad of their ending as of their beginning. Their object seems to be, to disgust their slaves with freedom, by plunging them into the lowest depths of dissipation. (10.17)
Douglass wants to show that the slave masters don't maintain their iron grip on their slaves by force alone. An important way they keep power is by deceiving their slaves into not understanding what slavery is. When they give their slaves a taste of freedom at Christmas, they trick them into getting drunk and degrading themselves, so that afterwards (when they're hung over) they associate those bad feelings with freedom and decide they don't want to be free at all. Slavery, in other words, depends on deception.