Anger is the key element of contention. People disagree all the time. If they discuss and work out differences without anger, they avoid contention.
The scriptures provide what, at first glance, may seem to be a mixed message on contention. On the one hand, we have this:
exhort you that ye should earnestly contend for the faith which was once delivered unto the saints.
Contend thou, therefore, morning by morning; and day after day let thy warning voice go forth; and when the night cometh let not the inhabitants of the earth slumber, because of thy speech.
(Doctrine and Covenants 112:5, an allusion to Isaiah 50:4 and 2 Nephi 7:4)
On the other, we have this:
For verily, verily I say unto you, he that hath the spirit of contention is not of me, but is of the devil, who is the father of contention, and he stirreth up the hearts of men to contend with anger, one with another.
(3 Nephi 11:29)
The key to reconciling the passages is the anger element. Anger is divisive and destructive. It generates heat but not light.
Cain was very wroth, and his countenance fell.
And the Lord said unto Cain, Why art thou wroth? and why is thy countenance fallen?
(Genesis 4:5–6, KJV)
Cain was very angry, and his face was downcast.
Then the LORD said to Cain, “Why are you angry? Why is your face downcast?
(Genesis 4:5–6, New International Version)