(Mat 5:6-8 ESV) 6 “Blessed are those who hunger and thirst for righteousness, for they shall be satisfied.
7 “Blessed are the merciful, for they shall receive mercy.
8 “Blessed are the pure in heart, for they shall see God.”
“Righteousness” can refer to God’s declaration that someone is righteous by grace or to this actual conformity to God’s will. In Paul, “righteousness” is usually a product of grace, that is, imputed righteousness. But in Jesus’ vocabulary, speaking to Jews, he usually demands obedience to Torah, especially the great principles of Torah. As McKnight explains,
The moment one defines righteousness as conformity to Torah or to God’s Word in Scripture, three things happen. First, the scope of Scripture, especially as we find the prophetic texts, focuses our minds on big issues like justice, mercy, peace, faithfulness, worship, holiness, and love. Second, we are pushed into seeing how Jesus himself understood Torah observance, and here we think immediately of two texts, the Jesus Creed of 22:34–40 [love God; love neighbors] and the Golden Rule of 7:12, so that for Jesus a “righteous” person was someone who loved God and loved others as himself. Third, we are pressed into considering the antitheses of 5:17–48, where surpassing righteousness refers to kingdom behaviors.
Scot McKnight, Sermon on the Mount (The Story of God Bible Commentary; Accordance electronic ed. Grand Rapids: Zondervan, 2013), 44.
To hunger and thirst after righteousness is to long for a world in which the great Torah principles of love predominate. For example,
(Deu 10:12-13 ESV) 12 “And now, Israel, what does the LORD your God require of you, but to fear the LORD your God, to walk in all his ways, to love him, to serve the LORD your God with all your heart and with all your soul, 13 and to keep the commandments and statutes of the LORD, which I am commanding you today for your good?
(Deu 10:17-19 ESV) 17 For the LORD your God is God of gods and Lord of lords, the great, the mighty, and the awesome God, who is not partial and takes no bribe. 18 He executes justice for the fatherless and the widow, and loves the sojourner, giving him food and clothing. 19 Love the sojourner, therefore, for you were sojourners in the land of Egypt.
In the Torah, love is not personal but a matter of conviction and discipline. It’s love for people who may be complete strangers. It’s love for those who need love.
The “merciful” in. v. 7 refers to those who respond to the needs of others in action. It’s not just a feeling but a willingness to act. “Mercy” is also a near synonym for grace, and so it’s likely that “they shall receive mercy” is a promise of forgiveness.
“Pure in heart” reminds us of —
(Psa 24:3-6 ESV) 3 Who shall ascend the hill of the LORD? And who shall stand in his holy place? 4 He who has clean hands and a pure heart, who does not lift up his soul to what is false and does not swear deceitfully. 5 He will receive blessing from the LORD and righteousness from the God of his salvation. 6 Such is the generation of those who seek him, who seek the face of the God of Jacob. Selah.
The pure in heart is the opposite of the hypocrite that Jesus later describes. He prays for the sake of being heard by God, not man. He gives for the sake those given to, not for praise by men. He goes to the Temple to worship just because he yearns to worship.
To “ascend the hill of the LORD” is to climb Mount Moriah to enter the Temple. God had a special dwelling in the Holy of Holies there. To go to the Temple was to seek the face of the Lord, except that no one expected to actually see his face, as his presence was hidden behind a curtain.
Jesus promises those who seek to worship him with a pure heart entry into the Holy of Holies itself, a face-to-face encounter with God. This will happen in the new heavens and new earth, as promised in Rev 22:20. But it happens even today, in a sense, because God lives within his children through his Spirit, moving his indwelling from the Temple to each Christian and to each congregation.
(2Co 3:16-18 ESV) 16 But when one turns to the Lord, the veil is removed. 17 Now the Lord is the Spirit, and where the Spirit of the Lord is, there is freedom. 18 And we all, with unveiled face, beholding the glory of the Lord, are being transformed into the same image from one degree of glory to another. For this comes from the Lord who is the Spirit.
In Paul says that we are like Moses, standing in the very presence of God, being transformed by the appearance of the glory of God through the Spirit. There is something about being a Christian and possessing the Spirit that is like seeing the very face of God.