If men had wings
and bore black feathers,

few of them would
be clever enough to be crows.
- Rev. Henry Ward Beecher

Photo courtesy PDPhoto.org
The symbolic meaning of the Raven  in Native American Indian lore describes the raven as a creature of metamorphosis, and symbolizes change/transformation.In some tribes, the Raven is considered a trickster because of its transforming/changing attributes.Often honored among medicine & holy men of tribes for its
shape-shifting qualities, the Raven was called upon in ritual so that
visions could be clarified.  Native holy men understood that what the
physical eye sees, is not necessarily the truth, and he would call upon
the Raven for clarity in these matters.Foremost, the Raven is the Native American bearer of magic, and a
harbinger of messages from the cosmos.  Messages that are beyond space
and time are nestled in the midnight wings of the Raven and come to
only those within the tribe who are worthy of the knowledge.The Raven is also called upon in Native ritual for healing purposes.
Specifically, the Raven is thought to provide long-distance healing.The Raven is also a keeper of secrets, and can assist us in
determining answers to our own “hidden” thoughts.  Areas in our lives
that we are unwilling to face, or secrets we keep that harm us – the Raven can help us expose the truth behind these (often distorted) secrets and wing us back to health and harmony.See also: Feather Symbolism in Native American Indian lore

 Celtic animal symbolism because it is a bird closely connected with battle and the Celtic goddess Morrigan, who was a remarkable prophetess (connecting oracle themes with the raven).For example, the raven's intelligence is possibly its
most winning feature. Indeed, these birds can be trained to speak. This
speaking ability leads into the legend of ravens being the ultimate
oracle.In fact, the raven is often heard to cackle utterances that sound like "cras, cras." The actual word cras is tomorrow in Latin. This lends more fuel to the legendary fires that distinguish
the raven as a bird who can foretell the future, and reveal omens and
signs.Countless cultures point to the raven as a harbinger of powerful secrets. Moreover, the raven is a messenger too, so its business is in both keeping and communicating deep mysteries.Raven symbolism of wisdom and knowledge-keeping is connected
with the Welsh hero Bran, the Blessed whose name means raven. Bran was
the holder of ancestral memories, and his wisdom was legendary.
So much so, that he had his head (the vessel of his powerful wisdom)
removed and interred in the sacred White Mount in London. Ravens are
still roosting there (in the Tower of London), and they're thought to
keep Bran's wisdom protected and alive by their presence. more about Bran on my Celtic skulls page here.
The raven is symbolic of mind, thought and wisdom according to
Norse legend, as their god Odin was accompanied by two ravens: Hugin
who represented the power of thought and active search for information. The other raven, Mugin represented the mind, and its ability to intuit meaning rather than hunting for it. Odin would send these two ravens out each
day to sour across the lands. At day's end, they would return to Odin
and speak to him of all they had spied upon and learned on their
journeys.

Odin was also known as the Raven God. He had many daughters
known as Valkyries who could transform into ravens . I like to think
Valkyries would ride as ravens after a bloody battle and whisper to the souls of fallen Norse warriors to raise up from their bodies and come with them, where
they would soar the skies to Valhalla. What a trip back home that would
be.
There's more good news about raven symbolism from the ancient Greeks and Romans. In spite of its midnight-colored feathers, the raven was a solar animal in this culture, and was associated with both Athena and Apollo, both deities closely affiliated with the sun, and the light of wisdom .

https://www.whats-your-sign.com/raven-symbolism.html

They slept until
the black raven,

the blithe hearted proclaimed the joy
of heaven

- Beowulf

To invoke Raven as bird of prophecy, you can use the old
English rhyme used to interpret omens by the number of ravens, crows, or rooks
seen in a flock:

One for bad news,Two for mirth.

Three is a wedding,Four is a birth.

Five is for riches,Six is a thief.

Seven, a journey,Eight is for grief.

Nine is a secret,Ten is for sorrow. Eleven is for love,Twelve is for joy                tomorrow    
                           
https://www.druidry.org/obod/lore/animal/raven.html