As I've outlined in other threads, I like the "be ye therefore perfect" injunction - but ONLY if it is understood as a gradual process of growth, enabled by grace, rather than a command to never make mistakes. Likewise, I like the focus on striving to understand the Gospel and keep the commandments - but ONLY if it is framed within the context of underpinning grace and mercy and love. My concern is that too many members adopt a perfectionist paradigm that creates an impossible standard by tying their acceptability to the Lord to how they do in comparison to others - that makes uncertainty and doubt and weakness and struggle bad things, rather than simply part and parcel of our mortal condition.
Here are the principles that I believe are the foundation of mortal peace:
1) "We see through a glass, darkly." (I Corinthians 13:12)
It helps me to remember that even Paul (the Elder McConkie of his time, in a way) admitted that "WE see in part, and WE prophesy in part" and "WE see through a glass, darkly" (1 Corinthians 13) - and even Nephi felt inadequate and prone to failure (2 Nephi 4). If that's true even of Paul and Nephi, it's fine to feel a bit lost and "clinging to the iron rod amid the mists of darkness".
Given that we all are feeling our way through the darkness,
2) "Then spake Jesus again unto them, saying, I am the light of the world: he that followeth me shall not walk in darkness, but shall have the light of life." (John 8:12)
Everything else is a human attempt to build on that foundation and bring meaning to life. All the rest, therefore, is secondary and supplemental. I'm not saying the rest is unimportant; I'm saying "The Church" is meant to enhance our individual AND communal pursuit of Christ-like development (not vice-versa), and that "the light of life" that will illuminate our way comes not through "The Church" (or any other external connection) but rather through an internal connection to Him.
In saying that, I am not downplaying the very real and powerful illuminating principles I find in Mormonism - and I am not saying that I believe all religions and denominations are equal in their ability to bring people to Christ (especially since I see Christ as the intermediary to bring us to the Father). I am emphasizing, however, what I believe to be the foundation of mortal peace - an internalization of the principle of grace, or Atonement, as it is called within Mormonism.
Therefore, the invitation I see is best stated in the passage:
3) "Come unto me, all ye that labour and are heavy laden, and I will give you rest." (Matthew 11:28)
I can't say what that means as a practical process for each and every individual, but I can say that I find peace in my effort to come unto him - and that my Church life has changed almost entirely into a way to serve others within my religious family. That has been an ennobling and enabling paradigm shift for me.