Message to Whiterun

Background
" I am to deliver a message to the Jarl of Whiterun. It is time for him to pick a side in the war and fight."

Stormcloaks
If you decide to side with the Stormcloak Rebellion, speak with Jarl Ulfric Stormcloak at the Palace of the Kings in Windhelm after delivering to him the Jagged Crown. He will tell you that it is time to deliver a message to the Imperialists of Whiterun and give you Ulfric's War Axe to deliver to Jarl Balgruuf the Greater in Dragonsreach. Travel to Whiterun and speak with Jarl Balgruuf the Greater. Upon completion of the conversation he will hand you back the axe, signifying that there will be a war. Travel back to the Palace of the Kings and speak with Jarl Ulfric Stormcloak once again. Upon completion of this conversation you may have to wait or exit the palace and then return. Upon your reentry Ulfric Stormcloak will initiate a scripted event during which he will request you report to Galmar Stone-Fist. Speaking to Stormcloak this second time will finish "Message To Whiterun" and start "The Battle For Whiterun."

Imperial Legion
If you decide to side with the Imperial forces, speak with General Tullius in Solitude after delivering him the Jagged Crown. He will tell you to deliver a message to Jarl Balgruuf the Greater in Dragonsreach. Travel to Whiterun, and speak to Jarl Balgruuf the Greater (be aware that you must have completed Dragon Rising before continuing the quest) and deliver the message. Upon delivering, he will converse with Irileth and Proventus Avenicci, and he decides to side with the Imperials. He will give you Balgruuf's War Axe, and ask you to deliver it to Ulfric Stormcloak in the Palace of the Kings, signifying that there will be a war. Ulfric will tell you to go back to Dragonsreach and give Jarl Balgruuf his axe back, and is disappointed that you did not side with the Stormcloak rebellion. Upon return, Balgruuf will not be surprised that Ulfric returned the axe, and he already requested that Tullius sends Legionaires to fight for Whiterun.Legate Quentin Cipius will be in Dragonsreach, and you will need to report to him, which ends "Message to Whiterun," and begins "Battle for Whiterun."

Known Bugs

 * The Jarl will sometimes disappear for no reason, the quest will point somewhere around Battle-Born Farm.
 * If you have started the companion questline, there is a chance the Jarl will disappear for the duration of the companion quests.
 * If you have already captured Odahviing in Dragonsreach, you won't have the option to give him the message. Finishing the game and returning to talk to him fixes this.
 * If you have started the quest Season Unending then there is no option for talking with the Jarl. There are only the dialog options for setting up the trap to capture Odahviing. There is currently no known fix other than to complete the game and return afterwords.
 * After giving the axe to Jarl Balgruuf the Greater, if you talk to Jarl Ulfric Stormcloak, he can ask you to deliver Ulfric's War Axe to Jarl Balgruuf the Greater again.
 * Sometimes when you try to finish the quest by talking to Legate Quentin Cipius he will not chat with you and instead say random lines about the war, making it impossible to carry on the quest (leaving the area and/or waiting seems to fix this)
 * Sometimes when talking to Legate Quentin Cipius, he will already be in a dialogue with an Imperial Soldier. Upon opening dialogue with the Legate, the imperial soldier will disappear. This, while funny, causes no known negative effects with the game.
 * If Legate Quenting Cipius is found sleeping upstairs above the Jarl's throne, sometimes he will not get up when speaking to you, nor will his mouth move.
 * If you join the Stormcloaks and deliver the Jagged Crown to Ulfric and HAVE NOT finished "Before the Storm," Jarl Balgruuf will not speak to you until you finish Dragon's Rising, and you cannot deliver the Axe from Ulfric. Also, Irileth and the Whiterun soldiers will disappear, leaving you to kill the Dragon on your own in Dragon's rising. The guards will appear shortly after you kill the dragon. Go through the dialogue with Balgruuf about being a dragonborn, then he will be able to receive the axe.
 * Sometimes if you start the quest before finishing Dragon's Rising you cannot finish the quest after finishing Dragon's Rising.

Tips

 * After Ulfric gives you back the axe you can train your sneak by backstabbing everyone in the room over and over. If you drain all of their health in one hit they will not react to your attacks. Do not try this on Ulfric or the guards. Works best in the map room with Galmar and Yrsarlad. Save often as sometimes the guards can spot you.
 * If you have not completed Bleak Falls Barrow you will have to complete that before he makes his decision.