Revelation 3:15-18

"I know your deeds, that you are neither cold nor hot. I wish you were either one or the other! So because you are lukewarm--neither hot nor cold--I am about to spit you out of my mouth. You say, 'I am rich; I have acquired wealth and do not need a thing.' But you do not realize that you are wretched, pitiful, poor, blind and naked. I counsel you to buy from me gold refined in the fire, so that you can become rich; and white clothes to wear, so you can cover your shameful nakedness; and salve to put on your eyes, so you can see."

I know your deeds
Revelation 2:2 "I know your deeds, your hard work and your perseverance. I know that you cannot tolerate wicked men, that you have tested those who claim to be apostles but are not, and have found them false." (Ephesus)

that you are neither cold nor hot
Romans 12:11 Never be lacking in zeal, but keep your spiritual fervor, serving the Lord.

You say, 'I am rich; I have acquired wealth and do not need a thing.'
Hosea 12:8 Ephraim boasts, "I am very rich; I have become wealthy. With all my wealth they will not find in me any iniquity or sin."
1 Corinthians 4:8 Already you have all you want! Already you have become rich! You have become kings--and that without us! How I wish that you really had become kings so that we might be kings with you!

But you do not realize that you are wretched, pitiful, poor, blind and naked
Proverbs 13:7 One man pretends to be rich, yet has nothing; another pretends to be poor, yet has great wealth.

buy from me gold refined in the fire
1 Peter 1:7 These have come so that your faith--of greater worth than gold, which perishes even though refined by fire--may be proved genuine and may result in praise, glory and honor when Jesus Christ is revealed.

and white clothes
Revelation 3:4 "Yet you have a few people in Sardis who have not soiled their clothes. They will walk with me, dressed in white, for they are worthy." (Sardis)

so you can cover your shameful nakedness
Revelation 16:15 "Behold, I come like a thief! Blessed is he who stays awake and keeps his clothes with him so that he may not go naked and be shamefully exposed."

(parentheses are mine)

Scriptures taken from the Holy Bible, New International Version® NIV®, Copyright© 1973, 1978, 1984 by International Bible Society. Used by permission. All rights reserved worldwide.