There are some fruits that will not keep. So there is in Christian work some fruit that does not last. There may be much that pleases and edified, and yet there is no permanent impression made on the power of the world or the state of the Church. On the other hand, there is work that leaves its mark for generations or for eternity. In it the power of God makes itself lastingly felt.
Fruit reveals the nature of the tree from which it comes.
The answer is simple. It is as our life abides in Christ, as we abide in Him, that the fruit we bear will abide. He chose you, and appointed you to bear fruit, and that your fruit should abide. He never meant one of His branches to bring forth fruit that should not abide. His electing grace, the surer my confidence will become that I can bring forth fruit to eternal life, for myself and others.