These verses come at the beginning of instructions on what Joseph Smith was to do about finishing the translation of the Book of Mormon after repentance for the loss of the 116 pages:
1 Now, behold, I say unto you, that because you delivered up those writings which you had power given unto you to translate by the means of the Urim and Thummim, into the hands of a wicked man, you have lost them.
2 And you also lost your gift at the same time, and your mind became darkened. (D&C 10:1-2)
Joseph Smith could have blamed Martin Harris or his wife or whoever it was who took the translated page, but the thing we learn here is that Joseph’s share of it was that he had delivered up the 116 pages to Martin in the first place. That was the part he was responsible for, and it was the gateway act. If he hadn’t given them the pages, then he wouldn’t have had any fault and there wouldn’t have been any opportunity for anyone else to lose them.
I think this teaches us that we need to think carefully about what we are really in control of. We don’t have control of what others do, but we have control of ourselves. Joseph had control of what he did with the translation and whether he kept the Lord’s commandments concerning it, but once he gave it away, he no longer had control. But by delivering it up to Martin Harris, he was complicit in the loss.
Another thing I notice is that it says that at the same time he delivered up the pages to Martin Harris, he lost his gift and his mind was darkened. This teaches the principle that the spiritual consequences for his part in the loss of the pages was immediate. There was no delay until hearing Martin lost them.
This is also true for us today. The spiritual consequences of our acts of rebellion and sin are immediate, even if it takes time for negative outcomes to manifest. Often we only notice we have sinned when we experience a negative outcome, but the spiritual consequences are immediate. We may not be sensitive to those consequences, but they are there. We lose spiritual gifts because the Holy Ghost can’t be with us constantly, and our minds are darkened.
The more sensitive we can become to the spiritual consequences, the more we will learn to repent quickly, whether we have a negative outcome or not.