Thunderous Might

Text:

Enchant creature
Whenever enchanted creature attacks, it gets +X/+0 until end of turn, where X is your devotion to red. (Each in the mana costs of permanents you control counts toward your devotion to red.)

Rulings:

• 9/15/2013 Numeric mana symbols (<img src="/Handlers/Image.ashx?size=small&amp;name=0&amp;type=symbol" alt="0" align="absbottom" />, <img src="/Handlers/Image.ashx?size=small&amp;name=1&amp;type=symbol" alt="1" align="absbottom" />, and so on) in mana costs of permanents you control don’t count toward your devotion to any color.
• 9/15/2013 Mana symbols in the text boxes of permanents you control don’t count toward your devotion to any color.
• 9/15/2013 Hybrid mana symbols, monocolored hybrid mana symbols, and Phyrexian mana symbols do count toward your devotion to their color(s).
• 9/15/2013 If an activated ability or triggered ability has an effect that depends on your devotion to a color, you count the number of mana symbols of that color among the mana costs of permanents you control as the ability resolves. The permanent with that ability will be counted if it’s still on the battlefield at that time.