It is not fashionable to preach about Hell or even to mention it. It is fashionable in modern religion to make the Church safe for warm fuzzies, for feel good religion. It is not fashionable even to mention death in church anymore. Is that not ironic? The one context in which we learn how to face death without fear, church, has become a venue in which we are supposed to avoid all mention of death. That time will come, when there will be no death, for Christ shall have come again. But, if we are to arrive safely at that destination, risen with Christ in glory to die no more, we need to prepare.
Jesus said those words the night before He went to His cross to die for our sins. He taught that, after he would rise from the dead, He would leave again to go to the Father (not by dying again, but by a mystery we call the Ascension), and that another Comforter (paraklētos) would come, that is, the Holy Spirit. And, although the Holy Spirit is another Comforter, that is, He is not the Son, still He is God and is One with the Father and the Son. When Jesus said "Without me ye can do nothing," and then spoke of His own Presence coming through "another (allos) Comforter." He made it clear, in saying these things, that He would be with us by the Holy Spirit. (That is because God is One. Where the Holy Spirit is Present in power to work in us, He brings the presence of the Father and of the Son.)
The Samaritan who had been healed of leprosy returned to the Lord Jesus to give thanks. The key is in that expression of gratitude. If you know the full weight of what has been done for you by God's grace, by Christ pouring out his lifeblood for you on the cross, by His rising again to remain forever the Mediator between God and man, and by pouring out that other Comforter on his Church, you will return to give thanks. If you know what was done for you in your own baptism, the cleansing and rebirth in Christ, you will return to fall at His feet and give thanks.
The fruit of the Spirit cannot be made by our efforts, but we cultivate that fruit by cooperating actively with God. To walk in the Spirit is active, not passive. Each day we need to return to the Lord to give thanks. We give thanks by hearing His revealed word in the scared Scriptures, by prayer, by the sacraments and by the fellowship of the Church. We are given grace, and our participation, fellowship and communion (all of which are summed up in the original Greek New Testament by one word, koinōnia) must be active, not passive. We should not sit back, passively, and assume the fruit will grow without our cooperation; for then the weeds would strangle it. The flesh would be overcome by every passion, and we would be lost.
No, we cannot make the fruit by our own hands; it grows by the power of the life within it. But, we can prevent its growth by failing to cultivate it, by failing to return to the Lord Jesus Christ to give thanks. Without Him we can do nothing. With Him, abiding in Him, we can bring forth much fruit. Our lives can become the blessed, holy and joyful fellowship with God that lasts forever, that proclaims Jesus, and that makes Him known to every person we meet, whether or not we say a word.