Quote 43
This is the penalty of telling the truth, of telling the simple truth, in answer to a series of plain questions. (3.5)
Douglass is telling the story of a slave who made the mistake of telling his master (whom he didn't recognize) the truth about his poor treatment. The slave was severely punished, showing that slave owners aren't interested in the truth. Instead of admitting that slavery is an oppressive system, the slave masters require that their slaves flatter them. This is probably related to the ways slave owners treat religion, using their version of Christianity to make themselves feel better, rather than facing the truth about slavery.
Quote 44
Mr. Gore acted fully up to the maxim laid down by slaveholders, -- "It is better that a dozen slaves should suffer under the lash, than that the overseer should be convicted, in the presence of the slaves, of having been at fault." No matter how innocent a slave might be -- it availed him nothing, when accused by Mr. Gore of any misdemeanor. To be accused was to be convicted, and to be convicted was to be punished; the one always following the other with immutable certainty. (4.2)
As Mr. Gore's conduct demonstrates, the rule for slaves is simple: the slave is always wrong and the master is always right. Douglass is showing us that slavery doesn't operate according to any principles of justice or fairness but is, instead, simply about power.
Quote 45
I remained firm, and, according to my resolution, on the third day of September, 1838, I left my chains, and succeeded in reaching New York without the slightest interruption of any kind. How I did so,--what means I adopted,--what direction I travelled, and by what mode of conveyance,--I must leave unexplained, for the reasons before mentioned. (11.5)
When Douglass escapes, he is still bound to a certain kind of secrecy. If he tells the truth about what happened and how he escaped, it could get the friends who helped him into trouble.