The Bible has a lot of warfare imagery in it.
It talks about...
... getting trained for battle (Ps. 144:1)
... being delivered from enemies (Dt. 20:4)
... fighting the good fight (1 Tim.6:12)
... and a whole lot more.
It's important to remember this warfare imagery isn't just a figure of speech.
We are in a real battle.
There really are dark, evil spiritual forces that seek to undo us and ruin our lives (Eph. 6:12).
But this is not to be a source of fear to us.
We have a King who is continually subduing us to Himself, defending us and conquering His enemies (Ps. 2:6-9).
So though we engage in battle, we do so as happy warriors.
"Praise the Lord! Happy are those who fear the Lord. They are not afraid of bad news; their hearts are firm, secure in the Lord. Their hearts are steady, they will not be afraid" (Ps.112:1,7-8).