The mention of newborn babies carries the reader back to the idea of new birth which Peter has already mentioned in 1.3 and 1.23. The Greek word for babies is used of infants who have just been recently born (compare Luke 2.12, 16, where the same word is used to refer to the newly born Jesus, and in 1 Thes 2.7, where it is used metaphorically, as here).
This metaphorical expression may be understood in two ways. On the one hand, it could mean that Peter’s readers are very recent converts; the possibility is even suggested that they have just been baptized. On the other hand, it could be that Peter is here echoing a prevailing idea in the New Testament, which is that a believer is always like a child, and therefore can be spoken of as recently born. Most translations preserve the ambiguity, but the Good News Translation, by rendering it in the imperative, seems to lean towards the second of these two alternatives.
In translating metaphors, one must be aware of three factors: the image, the topic, and the ground of comparison. This third factor is a particular trait or characteristic of the image which is applied to the topic. Here the image is newborn babies, the topic, Peter’s readers, and the ground of comparison is the newborn baby’s longing for milk. Some translations make this ground explicit, for example, Barclay “As newly-born children want nothing but their mother’s milk, so you must set your heart on the pure milk….” It is of course possible that in the figurative expression newborn babies there is the implication of innocence, since newborn babies are not in a position to engage in lying, hypocrisy, jealousy, and insulting language, but clearly the most immediate basis of comparison is the behavior of newborn children who want their mother’s milk.
The word translated always thirsty (literally “long for”) is a word which expresses intense, passionate, and strong desire for something. Many translators retain the imperative here (Revised Standard Version “long for”; Also Barclay above). This seems better, since emphasis is placed on the ground of comparison, and not on the image. The readers are not commanded to be like newborn babies, but rather to be thirsty always for spiritual milk, in the same way that newborn babies are always thirsty for their mother’s milk.
What does pure spiritual milk refer to? The clue to interpreting this metaphor is how one understands the word translated spiritual. This word (Greek logikos) is used only here and in Romans 12.1, and can be rendered in three ways: (1) “Of the word” that is, the word of God, or the Gospel, referred to in the previous section (1.23-25). Some scholars and translations opt for this alternative (for example, Barclay “the pure milk that flows from the word of God”; Kelly “the milk of the word”). (2) “Rational,” which is the common way the term is used in classical Greek literature, particularly among the Stoic philosophers. (3) “Spiritual.” Most commentaries and translations follow this interpretation. The milk spoken of is a figure referring not to physical milk which nourishes the body, but spiritual milk, which is nourishment for one’s spiritual existence. This is further explained in the last part of the verse: the readers are to drink of this spiritual milk in order that they may grow up and be saved (literally “grow up into salvation”). “Salvation” here can either refer to spiritual development and maturity in this life, or be taken eschatologically, as the full blessedness which God will bestow at the end of time, when Christ comes again (1.5, 7). The first of these two alternatives goes more naturally with grow up; however, the eschatological tone of the letter gives credence also to the second interpretation.
If one understands the Greek term logikos as referring to the word of God, it may be necessary to introduce a simile, for example, “always thirsty for the pure milk which may be likened to the word of God.” If, however, one interprets spiritual as being related to a person’s spirit, then it may be necessary to say “always thirsty for pure milk,” that is, milk for one’s spirit.
The expression of means indicated by the phrase by drinking it may be related to the result in a somewhat different way than is suggested by the Good News Translation. For example, one may translate so that by drinking it you may grow up and be saved as “so that you may drink it and thus you may grow up and be saved.”
Grow up is of course not a reference to physical growth but to spiritual growth, and therefore it is possible to render the phrase in some instances as “to grow up in your spirits” or even “to grow up in relation to God.”
Quoted with permission from Arichea, Daniel C. and Nida, Eugene A. A Handbook on The First Letter from Peter. (UBS Handbook Series). New York: UBS, 1980. For this and other handbooks for translators see here .