1 Nephi 17:25

Now ye know that the children of Israel were in bondage; and ye know that they were laden with tasks, which were grievous to be borne; wherefore, ye know that it must needs be a good thing for them, that they should be brought out of bondage.

You know the children of Israel were slaves. You know they had hard work to do. So you know it was good that they were freed from slavery.

“You know the Israelites were slaves. You know they carried crushing burdens. So you must see it was good for them to be set free.”