I like the opinions expressed in this post, and the thoughts given in reaching a conclusion as this. The fact that it highlights the link between a person’s nature and the quality of works they produce makes it relatable, as our level of consciousness and awareness always informs our actions.
Furthermore, you have identified that God is the only one who is truly good (Mk. 10:18). So, the ability to produce such good works will only be made possible by the adoption of His nature, which is made possible by the New Birth.This is why the quality of good works referenced in the given quote is presented as a consequence or by-product of a relationship with Christ, which is only available to the believer.
This implies that, such good work is powered by the Spirit of God; motivated by the love of God; and expresses the power of God in the life of the one who produces such fruits.
Therefore if the fruits of the spirit are the core of Christian character, this then becomes the force of attraction for the unbeliever, as it causes him to desire a similar experience. Thereby making for an effective witness for Christ (Matt. 5:16)