If you preach anything else except the new birth you will always get on well with your hearers; but if you insist that in order to enter heaven there must be a radical change, though this is the doctrine of the Scripture, it is so unpalatable to mankind in general that you will scarcely get them to listen. Ah! now ye turn away if I begin to tell you, that “except ye be born of water and of the Spirit, ye cannot enter the kingdom of heaven.” If I tell you that there must be a regenerating influence exerted upon your minds by the power of the Holy Ghost then I know ye will say “it is enthusiasm.” Ah! but it is the enthusiasm of the Bible. There I stand; by this I will be judged. If the Bible does not say we must be born again, then I give it up; but if it does then, sirs, do not distrust that truth on which your salvation hangs.
From the Metropolitan Tabernacle Pulpit, Volume 1, Sermon 14 by Charles Haddon Spurgeon