Knotvine Paladin

Oracle Text

Whenever Knotvine Paladin attacks, it gets +1/+1 until end of turn for each untapped creature you control.

Card Rulings

5/1/2009 The number of untapped creatures you control is counted as the ability resolves, and the bonus is locked in at that time. By this point, other attacking creatures will already be tapped (unless they have vigilance).