This is from Mosiah Chapter 8:20 "O how marvelous are the works of the Lord, and how long doth he suffer with his people; yea, and how ablind and impenetrable are the understandings of the children of men; for they will not seek wisdom, neither do they desire that she should rule over them!"
When I first read this verse, I took it to understand that the Lord suffers because of his people's stupidness (for lack of a better word). I think this is partially true. When we are dumb and sin/transgress the Word of God, He suffers (that's part of what the Atonement is about, isn't it?), But I don't think that is exactly what King Limhi meant when he said this. I think he meant that the Lord literally suffers with us. When we are suffering from transgression or bondage or from our own weaknesses- whatever it is that ails us- God suffers the pain with us, whether because of a decision we made or just because sometimes Life Hurts, God will not make us suffer alone. I am sure Mom and Dad understand this much better than I do, but it kind of reminds me of how, when Elliot broke up with me and I was aching, Mom and Dad wanted nothing but to see me happy again, and I think they were suffering with me. Sometimes I think we forget to see God as our loving heavenly Father. He is our parent.