18 Thus, the teacher of humility came not to do His own will, but the will of Him that sent Him. Let us come to Him, enter in unto Him, be ingrafted into Him, that we may not be doing our own will, but the will of God: and He will not cast us out, because we are His members, because He willed to be our head by teaching us humility. Finally, hear Himself discoursing: “Come unto me, you who labor and are heavy laden: take my yoke upon you, and learn of me; for I am meek and lowly of heart:” and when you have learned this, “you shall find rest for your souls,” from which you cannot be cast out; “because I have come down from heaven, not to do my own will, but the will of Him that sent me;” I teach humility; none but the humble can come unto me. Only pride casts out; how can he go out who keeps humility and falls not away from the truth? So much as could be said about the hidden sense has now been said, brethren: this sense is hidden enough, and I know not whether I have drawn out and shaped in suitable words for you, why it is that He casts not out him that comes unto Him; because He came not to do His own will, but the will of Him that sent Him.
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)