The Game has some friendly words of advice from one pot smoker to another -- telling Justin Bieber ... it's time he got smart about smoking pot ... and acquired a medical marijuana card.
Game -- a self-proclaimed weed enthusiast -- was getting his hike on in L.A. today when we asked about the Bieber pics, and Game replied, "Let's keep it real. There's a lot of people in high positions ... who smoke a little weed sometimes."
Game added, "I'm not saying it's okay ... but [Bieber] made a mistake. Forgive him. Let him go through the growing pains of his life."
And if Bieber REALLY needs to smoke out -- Game says it might be worth looking into getting a prescription ... for his glaucoma ... or insomnia ... or whatever else he can pull out of his ass on the fly.