The book of Jude is another letter written to try and combat heresy. Jude, possibly Jesus’ half-brother, urges his readers to “…contend for the faith that was once for all entrusted to the saints.” (Jude 1:3) He warns that Godless men have crept into the church “…who change the grace of our God into a license for immorality and deny Jesus Christ our only Sovereign and Lord.” (Jude 1:4b)
To put it simply, they were teaching that being saved by Grace, meant you could keep sinning and it would not held against you.
Jude reminds them that this is not how it works, and that they must not be so easily taken in.
Contend for the faith.
Your freedom is not to sin,
but to live in Grace.
I am particularly proud of the double meaning in line two. :-)