Try going into the souvenier shop and pressing a on the stone sculpture inside. Get rid of team rocket, go to the lake of Rage, surf to the red gyrados and either catch it or defeat it. You should then be able to go to the icy path to get to blackthorn city.
also you must kick team rocket out of goldenrod city
You must buy the ragecandy bar to get past but i did not i dont know how
Go to the lavender town radio tower and talk to the old man inside
You need to beat Team Rocket then Beat the gym leader and he'll go away
If you mean the man that stops you from going further east, you have to beat the gym. But then there is a man in front of the gym too and that might be the guy you talk about. In that case, you have to defeat team rocket who are hiding in a house with a "Weird looking tree" beside it. The hideout will be open when you catch or defeat the red Gyarados at lake rage.
you have to have beat the other 6 gyms. mahogany is the 7th.
As soon as you enter Mahogany Town, a man will give you Strength
Defeat team rocket
mahogany town talk to old man if he doesnt give it beat him up for it
you have to beat team rocket in mahogany town.
find lance at the lake of rage go back to mahogany town go in the house on the left and beat team rocket then beat the gym leader
u have to go to the 7th gym (ice type gym,Mahogany town) and talk to a man who is in behind poke center and next to a house
You must buy the ragecandy bar to get past but i did not i dont know how
first catch the red gyardos in the lake of rage by swimming up to it directly and then beat team rocket
Well, you don't. He stays there, nothing else to it.
you have to buy it i think. i dont really remember....
pewter, the old man on a hill
you have to save the director and beat archer of team rocket