The Weight of Glory is the title to a famous sermon Lewis wrote, it is also the title of a book including that sermon along with a collection of others. A Slip of the Tongue is the last one included in the book; below are some quotes from that sermon. It was a Spirit-prompting by which I read this sermon, and I'm glad I followed Him to this sermon - the words were both refreshing and reprimanding. They were like a blast of cold air which awakens and startles. Good stuff I needed to ponder.
When a layman has to preach a sermon, I think he is most likely to be useful, or even interesting if he starts exactly from where he is himself, not so much presuming to instruct as comparing notes. (pg 184)
Have we ever risen from our knees in haste for fear God's will should become too unmistakable if we prayed longer? (186)
Our temptation is too look eagerly for the minimum that will be accepted. (188)
For it is not so much of our time and so much of our attention that God demands; it is not even all our time and all our attention; it is ourselves. (189)
For he claims all, because he is love, and must bless, he cannot bless us unless he has us. When we try to keep within us an area that is our own, we try to keep an area of death. Therefore, in love, he claims all. There's no bargaining with him. (190)
What God does for us, God does in us. (191-2)
Failures will be forgiven, it is acquiescence that is fatal. (192)