I often think of this verse, I ask if I am a sheep or a goat, and if He knows me or not. I believe I am saved but I feel so far from where I imagine He wants for me, that I do question myself and my sincerity of devotion at times.
I am terrified by the verse, matthew 7:21-23.
It always reminds me of Lewis quote, its no good saying you choose to kneel once you can no longer stand.
"God will invade. But I wonder whether people who ask God to interfere openly and directly in our world quite realise what it will be like when He does. When that happens, it is the end of the world. When the author walks on to the stage the play is over. God is going to invade, all right: but what is the good of saying you are on His side then, when you see the whole natural universe melting away like a dream and something else - something it never entered your head to conceive - comes crashing in; something so beautiful to some of us and so terrible to others that none of us will have any choice left? For this time it will God without disguise; something so overwhelming that it will strike either irresistible love or irresistible horror into every creature. It will be too late then to choose your side. There is no use saying you choose to lie down when it has become impossible to stand up. That will not be the time for choosing; it will be the time when we discover which side we really have chosen, whether we realised it before or not. Now, today, this moment, is our chance to choose the right side. God is holding back to give us that chance. It will not last for ever. We must take it or leave it."
C.S. Lewis
I am feeling a lot like what you are feeling, I have so many flaws, but I do believe I am saved. Thank you for the quote, which gives the reality of when Jesus return to this world.