There is a saying amongst theology/seminary students that a little Greek is a dangerous thing. I'm not Greek so I can't really comment. Oh, wait. Greek language, not Greek origin.
The meaning behind the phrase is that it can be unhelpful for untrained or unqualified people to attempt to read and/or understand and/or translate and/or interpret the Koine Greek that much of the New Testament is written in. I presume this points to the potential dangers of misunderstanding, misinterpreting and misapplying the text.
Whilst there may be some truth in that, I think it's better to be dangerous than ignorant so I'm always willing to throw a little (dangerous) Greek into sermons I preach. I believe so doing can broaden our understanding and appreciation of what is written in the Bible and, by definition, what God is wanting to say to us through that medium. It can also serve to encourage people to look into these matters and develop their own little Greeks!
Some of the more loaded and significant Greek words I've come across over the years are rhema (spoken, personal word) and logos (written, unchanging word), koinonia (partnership, benefaction, fellowship), pistis (faith, conviction), exousia (authority) and dunamis (power), hagios (holiness, consecrated, blameless), sozo and soteria (verb and noun respectively meaning salvation, healing, deliverance, restoration, completeness). We could also consider that there are at least four different Greek words that are translated as "love" - agape (unconditional), philadelphia (brotherly), eros (sexual) and storge (familial) and some passage of Scripture miss these nuances if the translation or notes don't pick up on the difference.
A couple of examples of how our understanding a little Greek can help: When Jesus met with Zacchaeus recorded in Luke 19:9, Jesus says to Zacchaeus "Today salvation has come to this house, because he also is a son of Abraham;" The salvation that has come is the Greek soteria and points to completeness, deliverance, restoration and not just eternal security. It's much broader because the Kingdom of God is for both now and then - mortality and eternity. It results in changed lives here, today, not just in heaven, later.
Secondly, in Ephesians 6:17 where Paul exhorts believers to "take the helmet of salvation, and the sword of the Spirit, which is the word of God;" this word is the Greek rhema, not logos. It is a spoken word for a specific purpose rather than the eternal unchanging word of God. It is a word given to us by the Spirit for use at that moment in a spiritual battle rather than being the entire written corpus. It is a specific parry or thrust that will keep us in the battle.
So I'm all for little Greeks. And, as we know from acorns, from little Greeks, big Greeks grow.