Its building your speed from the get-go, and it has menace, so it'll probably help you damage your foes in the long run, especially on the early turns
It also reminds us that you cant tap the same Petitioners for multiple abilities, so dont try
Then exile it.) "Flashback [cost]" means "You may cast this card from your graveyard by paying [cost] rather than paying its mana cost" and "If the flashback cost was paid, exile this card instead of putting it anywhere else any time it would leave the stack." You must still follow any timing restrictions and permissions, including those based on the card's type
That's Orim's Chant in a nutshell: good for stopping an opponent in the middle of his combo while he has a bazillion mana floating and damned if he isn't going to take mana burn and die, but don't you just wish it was a cantrip
If they've already attacked, they remain attacking creatures