Growth in holiness requires growth in virtue. Charity (love of God, also extending to love of neighbor) is the greatest of the theological virtues, so, yes, growing in love for God is growing in holiness.
A sermon that stops there, though, doesn't give much in the way of instruction. "How do we grow in our love for God?" is the question that they often fail to answer.
-Practicing the other virtues
-Frequenting the sacraments
-Avoiding sin
Another good book is the 12 Steps to Holiness and Salvation in which the "steps" are broken down into: faith, hope, love of God, love of neighbor, poverty, chastity, obedience, meekness or humility, mortification, recollection, prayer and self-denial or love of the cross.
Oh thank you, Mater! I didn't know that St. Alphonsus wrote a book like this. He's one of my favorite saints. Yes, virtue is a part of growing in holiness, but I couldn't think about how to put it into words, if I write to the priest. Interestingly, I attended an NO parish (called St. Alphonsus) that celebrated St. Alphonsus feast day on Sunday before last. Well, the priest gave the usual peace and luv sermon about St. Alphonsus, but left out the fact that the reason that St. Alphonsus started his congregation of missioners is because he was concerned that country people were not properly catechized. Well, I wrote to the priest the next day, and reminded him of why St. Alphonsus started his mission, and I also complained, in a charitable way, about the priest concelebrating Masses with his new assistant priest. Well, he didn't write back, but I could tell that I struck a cord, because of what he wrote in the next bulletin (very negative reaction, which is unfortunate, because I was extremely charitable in my email to him). So even if a priest doesn't like what I tell him, he will have to read it and hopefully think about it eventually. I care very much about the sad situation in the NO church, and have pity for those who are stuck there. If there is a schism in the near future, it will be helpful for these priests to understand the fullness of the faith (though I'm a poor example of knowing what that is).
To get back to what you wrote, I appreciate that you gave the reminder that growing in holiness requires growth in virtue (Charity, which is love of God, extending to love of neighbor), so that indeed growing in love for God is also growing in holiness, and that a sermon that stops there doesn't give much in way of instruction. You're right in that they fail to answer how to grow in our love for God.
-Practicing the other virtues
-frequenting the sacraments
-avoiding sin
The twelve steps to holiness are helpful, too. I was thinking that I would have to write something (if I write to the priest) intellectual, but really, it can be kept quite simple, I think.