5 “My sheep hear my voice, and I know them, and they follow me: and I give unto them eternal life.” This is the pasture. If you recollect, He had said before, “And he shall go in and out, and find pasture.” We have entered by believing— we go out at death. But as we have entered by the door of faith, so, as believers, we quit the body; for it is in going out by that same door that we are able to find pasture. The good pasture is called eternal life; there no blade withers— all is green and flourishing. There is a plant commonly said to be ever-living; there only is it found to live. “I will give,” He says, “unto them,” unto my sheep, “eternal life.” You are on the search for calumnies, just because your only thoughts are of the life that is present.
Source: Tractates on the Gospel of John (New Advent)