In Leviticus 19:27 it says do not round your hair at the temple. Is that a form of submission to the Lord if not what does it mean?

Like many of the 613 Torah commandments, we don't know the precise "reason", but can only learn and suggest various "benefits" to their observance. The Rambam (Maimonides) and Ibn Ezra explain that priests in ancient religions shaved at least part of their heads as part of their idol worship, so we want no part of that. Rav Kook adds, that the nation of Israel is proud of our nationality, and are careful to keep that national "look" or fashion, and differentiate ourselves from gentiles, which would also prevent assimilation. Rabbenu Bechaya suggests that the laws of men's haircuts and not shaving particular parts, especially beards, differentiate between men and women to prevent gender confusion.