19 “And this,” says He, “is the will of the Father that sent, that of all that He has given me I should lose nothing.” He that keeps humility was given to Him; the same He receives: he that keeps not humility is far from the Master of humility. “That of all which He has given me, I should lose nothing.” “So it is not the will of your Father that one of these little ones should perish.” Of the proud, there may perish; but of the little ones, none perishes; because, “if you will not become as this little one, you shall not enter into the kingdom of heaven.”
“Of all that the Father has given me, I should lose nothing, but I will raise it up again on the last day.” See how here He delineates that twofold resurrection. “He that comes unto me” immediately rises again, being made humble in my members; but I will raise him up again on the last day also according to the flesh. “For this is the will of my Father that sent me, that every one who sees the Son, and believes in Him, may have eternal life; and I will raise him up on the last day.”
He said above, “Whoso hears my word, and believes Him that sent me:” but now, “Whoso sees the Son, and believes in Him.” He has not said, sees the Son, and believes in the Father; for to believe in the Son is the same thing as to believe in the Father. Because, “even as the Father has life in Himself, so has He given also to the Son to have life in Himself. That every one who sees the Son, and believes in Him, may have eternal life:” by believing and by passing unto life, just as by that first resurrection. And, because that is not the only resurrection, He says, “And I will raise him up at the last day.”
Source: Tractates on the Gospel of John (New Advent)