Jon Snow, for the moment, has not yet convinced Daenerys Targaryen to join forces and fight in the inevitable war with the dead as winter has finally come. The King of the North could mine enough dragonglass to make weapons but he still lacks an army big enough to fight the white walkers and its legion of wights. In order to win against the Night King, Jon Snow needs more men.
One possible solution is to seek help across the Narrow Sea and acquire an army of sellswords from Essos big enough to match the Night King’s army of the dead. But for this move to succeed, the King of the North needs the Iron Bank of Braavos.
Convincing the Iron Bank
However, the Iron Bank is currently doing business with Cersei now that she was able to acquire all the gold necessary to pay the Crown’s debt with the defeat of House Tyrell in episode 3 of "Game of Thrones" this season. The Queen plans to acquire the services of the Golden Company, an army of sellswords, to aid her war against the Mother of Dragons.
The Iron Bank has shown in the past though that it can invest in both sides of Westeros’ warring factions with the right convincing. Just ask the Onion Knight, Ser Davos Seaworth. After pointing out that the Iron Bank could lose its investments in Westeros with the death of Tywin Lannister and Tommen as King, the bank agreed to loan Stannis Baratheon the money needed to acquire more men and resupply his troops.
The Golden Company is not the only sellswords available in Essos since many of this army for hire groups are mentioned in the books. There are plenty of them in Braavos where Stannis recruited thousands for his campaign to get the Iron Throne.
Show them the wight
That the Iron Bank of Braavos can be a powerful ally to Jon Snow was suggested in an online article posted on Esquire.
The article quoted a Reddit user’s suggestion that the King of the North should “prioritize proving” to the Iron Bank the existence of the army of the dead and how the coming winter could completely destroy Westeros.
The Reddit user suggested that in order to do this, Jon Snow must convince the Iron Bank the same way his group plan to convince Cersei.
By capturing a wight and presenting the creature to them.
This way he can argue that should Westeros falls to the dead, the Iron Bank’s investments and interest in the continent will be wiped out or literally frozen. Simply put, it is in the best interest of the Iron Bank to help the fight against the Night King or they will see their precious gold turned to snow.
The bank cannot simply do business with the dead.