Paul and Peter both seem to use the word "logikos" once each. Peter tells his audience to "desire as newborn infants the sincere milk of the word" (in a popular translation), while Paul uses it to exhort the Roman Christians to respond to the mercies of God with a consecrated life "which is your reasonable service." Many commentators state that "logikos" tends to convey the idea of "sensible, rational" in koine Greek. One defense of the "milk of the word" translation is that there are enough meanings attached to "logos" that adjectivizing "logos" requires some context to unravel, as "logos" can mean concept, word, reasoning, idea, etc. One sense of "logikos" could be what we mean by "natural" when we say that naturally A was followed by outcome B. It is the sequitur in opposition to the non sequitur. When one meditates on the mercy of God, as Paul does throughout Romans 11, then naturally one would respond with a submission to God's will, as indicated in Romans 12:1. It is the sensible and obvious response.
And what about Peter? In the 2nd chapter of his First Epistle, laying aside all presumptuous conceits, as newborn infants we should desire the guileless, logikon milk, if we have tasted that the Lord is good. How can you crave the milk if you haven't tasted His goodness? When you have tasted the goodness, you will crave the guileless milk. It is the natural, sensible, visceral, obvious, and reasonably expected response. It is His goodness that draws people to repentance.
One of the first-shall-be-last-last-shall-be-first ironies of the New Covenant is that in order to be mature, one must crave the milk of His goodness. As with the Corinthians, trying to act like a Big Man only makes you a big baby in the kingdom of God. But if you want to be a grownup in the kingdom of God, you must become a big baby for the milk of Divine kindness. The guileless milk, if we desire it, immunizes us against the leaven of divisive self-importance which infected the Corinthian church.
Logikon doesn't need to be a direct reference to the Anointed Logos, to be about the Word. The milk is certainly the life-giving revelation of His goodness that nourishes and sustains us. Man shall not live by bread alone but by every word that proceeds (present tense) from His mouth.
In the Epistle to the Hebrews, the author warns the Messianic Jews that in order to not be derailed from entering the Divine Rest in His goodness, they need the milk of first principles: trust in God and repentance from dead works. The just shall live by faith, so these are not things we outgrow but things we incorporate into everything that is built on the foundation of grace and trust.
It is in being yoked into Christ's lowliness and gentleness and guilelessness that we heavyladen find rest for our souls. The Body of Christ grows, Paul tells the Colossians, when we hold fast to the Head of the Body. We will be fruitful, Jesus tells the Apostles, when we abide in Him as the grape branches abide in the vine. The Body is unified and grows, rather than divides, as we realize Who gives increase.
