There is only one reference in the Bible to a ‘lukewarm’ Christian and that is Revelation 3:15-16 which say;"I know your deeds, that you are neither cold not hot. I wish you were either one of the other! So, because you are lukewarm - neither hot nor cold - I am about to spit you out of my mouth". These words are written to a church in Laodicea and they certainly sting. That God would prefer a cold Christianity than the sort he finds here would have sent shockwaves in Laodicea. The Christianity that seems to have plagued Laodicea is what we call ‘lukewarm’. So, what is it? And if we are lukewarm are we saved?
Laodicea was a banking centre and a textile town and so was fairly wealthy. The churches crime was that if failed to find in Christ the source of all true wealth, splendour and vision. It is a situation of which we can relate to all too easily today living in Sydney. So, being lukewarm is akin to comfortable Christianity. One in which we think we are rich and prosperous and need nothing but fail to realise that we are wretched, pitiable, poor, blind and naked. It is this type of Christianity that causes Jesus to say that he wants to spit him out of his mouth! And God’s counsel to us is in Rev 3:19, where he says to Laodicea and to us; ‘those whom I love, I rebuke and discipline. So be zealous and repent’. Lukewarm Christianity is one that has lost its sense of being zealous. Paul actually tells us in Romans something similar, ‘never be lacking in zeal, but keep your spiritual fervour, serving the Lord’.
And this also answers your second question - even though Laodicea are lukewarm at this time Jesus says that he still loves them that is why he rebukes them and gives them counsel to turn away from their lukewarm lifestyle. If Laodicea has a chance then comfortable Christians also do but they need to listen to the persuasive counsel of God. He is the one who has come to them and he stands and he knocks and he calls to them to listen. For the only cure for lukewarminess is the readmission of the excluded Christ.