It wasn't until the very last scenes when it all became clear. Let's recap.
Andy Lau and Sammo Hung meet and become fast friends, with Andy referring to Sammo as "Big Brother." Then Andy's career takes off and he's given the "All-Piercing Spear," as phallic a symbol as any. This is followed by a scene where Sammo urges Andy to "ride swiftly" while Andy touches his chest while gagging on a mouthful of rice.
This subtext was such a pleasant surprise as everything else in the movie is so idiotically blunt and mentally un-challenging that I forgot to keep thinking and had to catch up every once in a while after dozing off.
Later in the film, Andy is wounded by Maggie Q in a duel and is tended to by Sammo, after the fight. One of Andy's soldiers offers to remove his armor, but Andy refuses, saying that he doesn't like showing his weaknesses. Andy then dismisses everyone, except Sammo. Alone, they then exchange a knowing glance and offer each other tissue and ointment.
This is a good time to note that the film's title, 三國之見龍卸甲, literally means "see the dragon, shed the armor," a clear metaphorical and synecdochical reference to Andy's "dragon" and attire.
Andy's soldiers then suddenly return to report that Maggie Q's army is attacking again. Andy immediately orders his entire army to certain death by Maggie Q's lute-playing/Mandarin ghost-voiceover-er.
Everyone dies, except for Sammo, of course, who stays behind. Sammo asks Andy if he'll surrender, but is laughed off. This is when Sammo breaks down and admits his betrayal of him in favor of Maggie Q. Why? Because he's been giving and giving and giving all these 32 years, and what's Andy given him? Nothing! Just endless exotic trips into the unknown while he stayed behind. What about his needs? What about his wants? All he wanted was for his name to lie next to Andy's when they got home from the war, but, alas, they're still fighting in circles in the sand.
I cried at this point. Tears were streaming.
Andy is crestfallen, but philosophical. He tells Sammo that he had stripped him of his armor. In other words, Andy had shown him his dragon, he had shed his armor, and as a result, his weakness was revealed: his true love, blind, unconditional love... That still holds true.
Clearly touched, Sammo helps Andy out of his clothes, resurrecting his dragon one last time.
Before, weakened and armor-less, Andy, that vain bastard, orders Sammo to ring a gong and shout his name a few more times...
As he charges alone towards the army of hundreds and his own certain death.
Three Kingdoms: Resurrection of the Dragon: 3/10