Gather Courage is a common Instant card from Ravnica: City of Guilds (RAV), collector number 165. Current market price: $0.15 (foil $0.43), TCGplayer market prices via Scryfall.
Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.) Target creature gets +2/+2 until end of turn.