What did he learn from this incident

White Fang learned that obedience and loyalty were things to be rewarded.

"When Mit-sah told the story in camp, Grey Beaver ordered meat to be given to White Fang. He ordered much meat to be given, and White Fang, gorged and sleepy by the fire, knew that the law had received its verification.

It was in line with these experiences that White Fang came to learn the law of property and the duty of the defence of property. From the protection of his god’s body to the protection of his god’s possessions was a step, and this step he made. What was his god’s was to be defended against all the world—even to the extent of biting other gods. Not only was such an act sacrilegious in its nature, but it was fraught with peril. The gods were all-powerful, and a dog was no match against them; yet White Fang learned to face them, fiercely belligerent and unafraid. Duty rose above fear, and thieving gods learned to leave Grey Beaver’s property alone."