Exegesis:
kai egeneto ‘and it was’ plus the verb in the indicative (ēlthen ‘came’) is one of the three ways in which the Septuagint and the N.T. translate the Hebraism wa-yehi … wa (‘and it was … and’); in the Greek, the clause that follows is logically the subject of egeneto ‘it was.’ This connective phrase has virtually no meaning and is disregarded by Revised Standard Version.
en ekeinais tais hemerais (8.1; 13.17, 24) ‘in those days’ is another Hebraism (cf. Ex. 2.11), and relates in a general way that which follows with what precedes.
apo ‘from’ goes with ēlthen ‘came’ not with Iēsous ‘Jesus’: ‘came from Nazareth of Galilee….’
ebaptisthē eis ton Iordanēn ‘he was baptized in the Jordan.’ There is no difference between ‘baptized en’ (v. 5) and ‘baptized eis’ here.
Translation:
If a language has a kind of introductory and transitional particle equivalent to the Greek kai egeneto ‘and it happened’ (translated traditionally as ‘it came to pass’), one can and should employ it, but more frequently than not, it is better simply to omit such elements, particularly if instead of contributing to the meaning, they tend to interrupt the sequence, distract the reader or lead to misunderstanding.
In those days may be rendered in some languages as ‘at that time’ or ‘then.’ This Semitic idiom is only a general phrase indicating temporal sequence.
In some languages proper names which are entirely unfamiliar may require some type of descriptive classifier. Hence one may translate ‘from Nazareth town in the Galilee province … Jordan river’ (Otetela). In view of the fact, however, that ‘river’ is used with ‘Jordan’ in verse 5, this last classifier may not be necessary.
In languages in which passive constructions must be or are usually shifted to active ones, the second part of this verse may be readily changed to read, ‘John baptized Jesus….’
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 .