Meier provides background information on the structure of OT beatitudes in the Psalms and Proverbs. He states that "sometimes the reward or fortunate consequence of such wise action is mentioned in the context," as in verse 3 of Psalm 1 (shall be like a tree planted near streams of water). Meier at 324.
After the exile, the beatitudes become more realistic (Book of Job), and then after the Seleucid persecutions with apocalyptic literature the horizon extends to the next world, and we see this view of the future kingdom in the beatitudes of Jesus.
Jesus' beatitudes come in this form: 1) the makarios (happy are), 2) followed by the designation of the sufferers and 3) the hoti or causal clause which promises the reversal of their "present misery" by an eschatological gift or action from God. Meier at 330.
In the background here is "the whole OT picture of God as the truly just king of the covenant community of Israel, the king who does what Israel's human kings often failed to do: defend widows and orphans ...." Meier at 331.
In Jesus' beatitudes:
“We begin to see why Jesus was not interested in and did not issue pronouncements
about concrete social and political reforms, either for the world in general or for
Israel in particular. He was not proclaiming the reform of the world; he was
proclaiming the end of the world.”
Meier at 331. Here Jesus differs from the prophets who were concerned about the social and political evils of their day. Jesus, by contrast, did not denounce slavery, Roman rule in Judea, unjust economic practices “oppressing the poor in the face of inflation,” because:
“The definitive arrival of God’s kingly rule was imminent; calls for social and
political reform, launched - and often botched - by human beings, were thus beside
Meier at 331.