The Purple on the Shield is the Colour which represents Kahnawake.
The Shield is a representation of God our Shield and Protector.
The 5 arrows bound together represent the 5 tribes of the Iroquois Confederacy, of which the Mohawks are one.
The 5 arrows are also a reference to King Jehoash who only struck the ground 3 times for victory, reminding us to ask and expect greater things from God. (see 2 Kings 13:13-19)
The flaming dove represents the Holy Spirit, and Pentecostal Fire.