Heretical Unity?

I heard an interesting definition of heresy the other night. The argument basically went that heresy, in addition to meaning all of the usual lack of doctrinal conformity, should include those who seek to destroy the unity of the church. Therefore, a heretic may be someone who has the catechism nailed, the Psalms memorized, crosses "t's" and dots all the "i's", but takes Christ's seemless garment and rends it in pieces. So we further fragment and reunite in what is often the case, and I am only meaning Christians here, a bond of heretical unity.

Holy Spirit and Scripture

Are the Scriptures the best tool and the Holy Spirit the best gift? Considering that the Holy Spirit 1) is God dwelling among us, 2) is called the comforter, and 3) (among many other things) is the one who enables us to read and understand the Scriptures.