How does beowulfs mission reflect a cycle of revenge

The epic of Beowulf was written about a thousand years back and there is a clear cycle of revenge portrayed in that.

Grendel the beast gets angry and attacks the Hall killing people, next comes Beowulf who kills Grendel for glory as well as for revenge purposes. Grendel’s mother attacks the kingdom to take revenge and in return killed by Beowulf, making it clear that revenge is a never ending cycle.