Lukewarmness I account a sin, as great in love as in religion.
— Abraham Cowley

Before water generates steam, it must register 212 of heat; 200 will not do it. The water must boil to generate enough steam to move an engine. lukewarm water will not run anything. lukewarmness will not generate life's work.
Unknown lukewarm quote

It seems safe to say that significant discovery, really creative thinking, does not occur with regard to problems about which the thinker is lukewarm.
— Mary Henle

Grief is hard on friendships, but it doesn't have to be. Sometimes, all it takes is a little honesty between friends. If we gently and lovingly explain what we need from the relationship during our time of grief, and what we are willing to do in return, we can turn even a lukewarm friendship into something special.
— Margaret Brownley

Never forget that God tests his real friends more severely than the lukewarm ones.
— lukewarm quotation by Kathryn Hulme