Bidding is what somebody has ordered you to do. Do his bidding, at her bidding, do the bidding of others.
It survives almost entirely in do somebody's bidding, which is disapproving — it says the person is acting as an instrument rather than by choice. This is the old sense of bid meaning to command, not the auction one. Note that bidding at an auction is a different word doing a different job, and bidding in bridge is a third; English collapsed two Old English verbs into one bid and has been slightly confusing ever since.
1nounbiddingWhat somebody has ordered you to do.
“The servants hurried to do the king's bidding.”
2nounmakingThe making of offers at an auction.
“The bidding for the painting started slowly, then rose quickly as two collectors competed.”
bidding is a command, or an offering.
Practised in A Song of Ice and Fire