Exegesis:
ēsan … kathēmenoi kai dialogizomenoi ‘were … sitting and questioning’: these verbal phrases, consisting of the imperfect of eimi ‘to be’ plus the present participle of the main verbs, denote continuous action.
tines tōn grammateōn (cf. 1.22) ‘some scribes.’
kathēmenoi (2.14; 3.32, 34; 4.1; 5.15; 10.46; 12.36; 13.3; 14.62; 16.5) ‘(were) sitting.’
dialogizomenoi (2.8; 8.16, 17; 9.33; 11.31) ‘considering,’ ‘pondering,’ ‘reasoning.’ Moulton & Milligan note that in the N.T. the word always has the sense of “inward deliberation or questioning.”
en tais kardiais autōn ‘in their hearts’: the meaning is the same as ēn heautois ‘in themselves’ of v. 8.
kardia (2.8; 3.5; 6.52; 7.6, 19, 21; 8.17; 11.23; 12.30, 33) ‘heart’: in Hebraic thought the heart is the center of intellectual activity. Lagrange points out that the same concept was true also of the Latins and even of the Greeks. The narrative throughout makes clear that this questioning carried on by the scribes was wholly internal and not outwardly expressed. Cf. Abbott-Smith: “say to oneself, i.e. think, reflect, without saying anything aloud.”
Translation:
Now is transitional, introducing a new aspect of the situation; it is not temporal.
For scribes see 1.22.
Questioning can be quite well translated as ‘thinking’ or even ‘speaking to themselves in their hearts.’
Though the heart is spoken of in the Bible as the center of intellectual and emotive elements of human experience, in other languages the heart may have no such value. In some languages the corresponding centers are the viscera (Conob), the liver (Laka), the stomach (Uduk), the gall (Toraja-Sa’dan) and the head (Anuak), though in the neighboring Shilluk demons may be in one’s head, but the liver and heart are the center of most other psychological activities. Whether one is to use ‘heart’ or some other part or organ of the body depends entirely upon the manner in which in any language such psychological experiences are described.
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 .