I believe you get them from the warden in Fuschia city. He gives it to you if you bring him golden teeth because he cannot talk well. Golden teeth are located in the safari zone right by the house where you get surf. In the house where the Warden is on the right of the cliff where the Gym and Pokemon center are, there is a rare candy right by the Warden but you must move the boulder to get it.
Good Luck
You get it from a sailor in the Olivine Cafe next to the Pokemon Center in Olivine City.
It's in Rusturf Tunnel
Find the Gold teeth in the safari zone. Go talk to the Warden (right of the Pokemon Center) and he will give you hm 04- strength.
They need HM 04 Strength Surf and waterfall
you have to go to mt. mortar (east of ecruteak town) and a guy will jump out of the cave and will give you hm 04 strength
HM 04 is Strength. It is found on the top floor of the Lost Tower (that tall white building near Solaceon town)
You can find HM Strength south of Soleacon Town at the top of the Lost Tower. One of 2 ladies at the top gifts you with this.
HM STRENGTH HM STRENGTH
Strength and Surf.
HM 4
Go to Nimbasa City (Raimon City), then in one of the houses on the left, talk to a blue head boy in there and he gives you hm 04 strength hope this helped!
You need to have a Pokemon that knows the move Strength (HM 04). But if you have a Pokemon that can learn it but you only want to use the move once, be warned, once the Pokemon learns a HM move, it cannot be erased, or you might say, it cannot learn a move in replace of it.
There are 8 HM's: Hm 01: Cut Hm 02: Fly Hm 03: Surf Hm 04: Strength Hm 05: Defog Hm 06: Rock Smash Hm 07: Waterfall Hm 08: Rock Climb
a guy in a house on the north side of the battle institute in nimbassa city gives you hm 04 streangth HOPE THIS HELPS :)