Everyone at one stage in their lives has exercised their faith. Therefore if it’s possible for an atheist to have faith in someone else’s story, including their own judgment of a situation facing them, then it’s equally possible for them to have faith in Christ. Go ahead and go up to an atheist and tell him his house is on fire with his wife and kids inside, make it sound believable and watch him gather his lawyers to make an assessment before he believes you. Will he do that? Highly doubt it.
I say this because many atheists criticise the use of faith and that we believe in something or someone without evidence. How many of us ever questioned the love of our wife and demanded visible evidence that she would love and serve us all the days of her life like she vowed upon the altar? We didn’t, we simply leapt into her arms, exercised our faith and said yes to marriage and yes to her love.
Christians love of Christ therefore, does not rest upon evidence alone but an understanding, like that of a future husband who will never fully understand the mind of his wife, Christians understand that we will never come to fully know Christ but we love him regardless, have faith in his testimony as well as that of his apostles and we just throw ourselves into his arms.