So, how does Pennington justify this choice?
A critical piece of Pennington's argument concerns how makarios maps onto the Old Testament.
To appreciate this argument, a quick historical recap is in order. As you know, the Old Testament was written in Hebrew. However, around 250–200 BC, a few centuries before Jesus, Jewish scholars translated the Old Testament into Greek. This translation was called the Septuagint. And the Septuagint was the Bible of the apostles and early Christians.
As a Greek translation of the Old Testament, the Septuagint allows scholars to correlate Greek words in New Testament with Hebrew words in the Old Testament. The process is simple. For a given Greek word in the New Testament we can observe where that same Greek word shows up in the Septuagint. We then examine the Hebrew words associated with the Septuagint's translation. This method helps correlate Old Testament meanings with New Testament words.
Okay, so where do we find the Greek word makarios used in the Septuagint? What Hebrew words are associated with it?
To start, Pennington notes that it's rare to find in the Septuagint a strict one to one correspondence between a Greek word and an associated Hebrew word. That is to say, we don't often find Greek/Hebrew synonyms. Mostly what we find in the Septuagint is a variety of Hebrew words associated with a single Greek word. But against that general trend, we do find an exception with the Greek word makarios. As Pennington observes, the Hebrew word asre in the Old Testament is always translated as makarios in the Septuagint. This suggests a tight correspondence between the Hebrew asre and the Greek makarios.
So, what does asre mean in the Old Testament?
To start, while there is some debate here, the word asre come from Semitic and Egyptian roots meaning "prosperity, good luck, and happiness." Crucially, asre is mainly found in the Wisdom tradition of the Old Testament, mostly Psalms and Proverbs. Of the forty-five occurrences of asre in the Old Testament, twenty-six are from the Psalms.
This connection with the Wisdom tradition is important for Pennington. The Wisdom tradition is less invested in the "if/then" contingencies of the Deuteronomic covenant, especially how those relate to the cultic practices of Israel. The Wisdom texts are more interested in a life well-lived than in adherence to Levitical prohibitions. As Pennington summarizes, "Asre describes the happy state of the one who lives wisely. In this sense it is closely related to salom [shalom]." Pennington continues:
Thus, asre refers to true happiness and flourishing within the gracious covenant God has given. Like the prophetic literature, the Psalms offer the promise of flourishing and happiness (fertility, prosperity, security) through faithfulness to the Lord...There is a struggle in Israel about which way to live, and the Psalms play an important part in creating the vision of the only path to true flourishing...
The other place asre regularly occurs is Proverbs, which also makes an appeal to find full human flourishing through wise living. In Proverbs the asre one is primarily the person who finds wisdom and lives wisely...This person is naturally extolled as "happy" and "flourishing."
We can observe this holistic view of flourishing in how asre regulates the vision of Psalm 1:
Blessed [Hebrew: asre; Septuagint: makarios] is the man
who walks not in the counsel of the wicked,
nor stands in the way of sinners,
nor sits in the seat of scoffers;
but his delight is in the law of the Lord,
and on his law he meditates day and night.
He is like a tree
planted by streams of water
that yields its fruit in its season,
and its leaf does not wither.
In all that he does, he prospers.
Notice what we have here in Psalm 1. A picture of human human flourishing. The one who is makarios is nourished ("like a tree planed by streams of water"), full of vitality ("its leaf does not wither"), and fecundity ("yields its fruit in its season"). Simply put, the one who is makarios "prospers."
The point for Pennington is that this vision of asre in Psalm 1 isn't a vision of behavior/reward, that if I do X then I will receive Y. That sort of if/then contingency is how we often think of the Beatitudes, that if I am, say, pure in spirit then I will receive a reward/blessing. By contrast, the vision of asre in the Wisdom tradition, argues Pennington, is describing something more organic, integral, and holistic. Not blessing as mere reward, but a vision of human flourishing--an integral way of being in the world characterized by vitality, fecundity, and prosperity.
If this is so, then the Beatitudes aren't setting before us a command/reward framework. "Do X and you will be Blessed." Rather, in the Beatitudes Jesus is describing a, very paradoxical, vision of human flourishing itself.

