From a sermon by Charles Haddon Spurgeon entitled “Testimony and Experience,” delivered June 2, 1872.

The most important question concerning any man living is this, is he a saved soul or no? It is of comparatively little consequence whether he be rich or poor, educated or uneducated, compared with this. Is he among the living before God or is he dead in sins? Is he pardoned or unpardoned? Is he a child of God or an heir of wrath? Is he walking in the darkness or has he passed into the light? Hence of all the days of a man’s history the most important is the day in which he is born again.

If the man be indeed saved, and a new man in Christ Jesus, he will look back upon the day of his regeneration as his chief birthday. His new birth is second in order of time, but he will always put it first in importance. His birth gave him his being, but his new birth secured his well being. Being born first we might have descended into hell; but, being born a second time we are secured for heaven.

Source : http://www.thedailyspurgeon.com