Exegesis:

estin … eisporeuomenon ‘is … going in’: although Translator’s New Testament treats this as a compound verbal phrase meaning simply ‘enters,’ the majority of translations, like Revised Standard Version, separate the two, translating ouden estin ‘there is nothing,’ and eisporeuomenon ‘which goes in’ as an independent participle modifying ouden ‘nothing.’

eisporeuomai (cf. 1.21) ‘go in,’ ‘enter.’

exōthen (7.18; cf. exō 3.31, 32) ‘from without,’ ‘from the outside.’

koinōsai (7.18, 20, 23; cf. koinos 7.2) ‘to make common,’ ‘to defile.’

ekporeuomena (cf. 1.5) ‘the things which go out’: the reference, of course, is to passions, sins and evil desires, catalogued in vv. 21-23, which have their origin inside the man, in his heart, and are outwardly expressed in sinful deeds and words.

Translation:

Nothing going into him must be made somewhat more specific in some languages, for this could be understood as referring to being wounded by a spear, pierced by an arrow, or stabbed by a knife. Obviously the meaning here is ‘eating,’ and hence in Guerrero Amuzgo the translation is ‘nothing that he eats.’

For defile see 7.2, but in this context it may be necessary to translate ‘make him bad’ or ‘cause him to sin.’

The phrase the things which come out of a man has been grossly misinterpreted in some translations to mean the excretion of body wastes, vomiting, an the discharge of mucus from the nose. In order that these ‘things which come out’ may be identified as behavior, one may add ‘out of the heart’ (Tzeltal), or say ‘what he does and says.’

Quoted with permission from Bratcher, Robert G. and Nida, Eugene A. A Handbook on the Gospel of Mark. (UBS Handbook Series). New York: UBS, 1961. For this and other handbooks for translators see here .