The Mahayana teachings are sometimes classified as either "nitartha" (definitive) or "neyartha" (provisional). Whether a Sutra belongs to one or the other classification seems to depend on which school of Buddhism you follow.
I also recently came across the following Pali Sutta:
"Monks, these two slander the Tathagata. Which two? He who explains a discourse whose
meaning needs to be inferred as one whose meaning has already been fully drawn out.
And he who explains a discourse whose meaning has already been fully drawn out as one
whose meaning needs to be inferred. These are two who slander the Tathagata."
("Neyyatha Sutta: A Meaning to be Inferred" (AN 2.25),translated from the Pali by Thanissaro Bhikkhu. Access to Insight, 8 August 2010, http://www.accesstoinsight.org/tipitaka ... .than.html
. Retrieved on 31 May 2013.)
What guidelines can we employ in order to avoid misinterpreting a Sutra?