According to Celestial regarding one of her dreams, dogs to God represent fallenness, rejection and reproach. Essentially almost whatever that is forbidden and abhorred by the Lord, not helped by that literal dogs are now regarded as the third worst invasive species after cats and rats. This is what I got from listening to a sermon on YouTube about the topic of ‘beware of dogs’ and this was got brought up in some way, in which whatever the Bible says about something turn out to be true. Well in some way or another in this case, though that doesn’t mean positive portrayals of dogs don’t exist in the Bible.
It is however rare and often in the context of either shepherding (Job), comeuppance (what Jezebel got), helping those in need (what Jesus said regarding poor people going to Heaven) and also in the apocryphal Book of Tobit. This also gets played out within the wider scope of Christianity, there are uses for dogs in Christian monasteries. Among those are guarding, hunting vermin (as it is in Arizona, USA) and helping the blind. There are some Christian saints associated with dogs, though it’s possible the thing with Jezebel is a matter of God using the wicked to punish the wicked. Dogs are one of those in this regard.
Then there is the association with dogs with witchcraft, as it is with some folk demonologies whether in early modern France or contemporary Ghana. It doesn’t help when there’s a Bible verse that mentions dogs together with witches (though this is helped by a sermon that I listened to before), that it seems dogs will usually be portrayed in a suspicious manner throughout the Bible and to some extent, Christianity as a whole given they’re seen as unclean in the Eastern Orthodox Church.