It seems that Jude verse 6 is referring to God confining the fallen angels who rebelled in an additional way, likely the "sons of God" incident in Genesis chapter 6.
Kwa nini Mungu kuwafunga malaika wengine walioanguka, lakini kuruhusu kiongozi wa uasi kubaki huru? Inaonekana kwamba Yuda mstari wa 6 inamrejelea Mungu kuwalazimu malaika walio anguka, walioasi katika njia ya ziada, kuna uwezekano "wana wa Mungu" tukio katika Mwanzo sura ya 6.