Are lukewarm believers saved?

The context of what Jesus Christ was saying is in the background of the ancient Near East. Laodicea is the recipient of water from Hierapolis and Colossae through the aqueduct that the Roman built. This is because Laodicea has no good water source. The city of Hierapolis gives hot water that brings healing from their hot spring while Colossae is their source of refreshing cold water that comes from their snowy mountain. Unfortunately, by the time these waters reach Laodicea, they are already tepid, which is good for nothing. The same is true for Christian adherents who believe they are spiritually doing good but are actually lacking. Their hearts are being prodded by the Lord in order for them to savor their fellowship with Him. And such Christian adherents will merely be in attendance on the day of judgment, receiving little in the way of rewards. Those who have triumphed will be honored by Christ Himself (See Rev. 3:14-22).