Is Steadfast Guard legal in Standard, Modern, and Commander?

Steadfast Guard is legal in: Modern, Legacy, Vintage, Commander, Pauper.

Steadfast Guard

Q: What type of card is Steadfast Guard?

Steadfast Guard is a Creature — Human Rebel. Its oracle text reads: "Vigilance (Attacking doesn't cause this creature to tap.) *"Best leave your tongue in its yap-hole, Mercadian scum, for your silvered words and golden bribes do not sparkle so brightly outside your city."* Power/Toughness: 2/2"