This is a saying from the Pali canon, upadhi dukkhassa mūlanti, which means “Attachment is the root of suffering.” So this is a genuine canonical quote.
You’ll find it in this sutta, but translated by Thanissaro as “Acquisition is the root of stress.” His translations are rather idiosyncratic.
In this translation of the same sutta it’s “acquisition is the root of suffering.”
Bhikkhu Bodhi’s translation (not available online, but in The Middle Length Discourses of the Buddha, page 868) has “attachment is the root of suffering,” although he sometimes has “acquisition” in place of “attachment,” in various repetitions of the phrase.
“He who can curb his wrath as soon as it arises, as a timely antidote will check snake’s venom that so quickly spreads — such a monk gives up the here and the beyond, just as a serpent sheds its worn-out skin.”
This is a genuine quotation from the Buddhist scriptures. It’s from the Sutta Nipata
“Know from the rivers in clefts and in crevices: those in small channels flow noisily, the great flow silent. Whatever’s not full makes noise. Whatever is full is quiet.”
The Buddha