Charles Haddon Spurgeon said this quote

[Jesus] did not say, 'Simon, son of Jonas, fearest thou me.' He did not say, 'Dost thou admire me? Dost thou adore me?' Nor was it even a question concerning his faith. He did not say, 'Simon, son of Jonas, believest thou in me?' but he asked him another question, 'Lovest thou me?' I take it, that is because love is the very best evidence of godliness. Love is the brightest of all the graces; and hence it becomes the best evidence.