To hunger and thirst after righteousness is nothing but the longing to be positively holy.
I cannot think of a better way of defining it. The man who hungers and thirsts after
righteousness is the man who wants to exemplify the Beatitudes in his daily life. He is a man
who wants to show the fruit of the Spirit in his every action and in the whole of his life
and activity. To hunger and thirst after righteousness is to long to be like the New Testament
man, the new man in Christ Jesus. That is what it means, that the whole of my being and the
whole of my life shall be like that. Let me go further. It means that one’s supreme desire
in life is to know God and to be in fellowship with Him, to walk with God the Father, the Son
and the Holy Spirit int he light. ‘Our fellowship’, says John, ‘is with the Father, and with
His Son Jesus Christ.’ He also says, ‘God is light, and in him is no darkness at all.’ To be
in fellowship with God means to be walking with God the Father, Son and Holy Spirit in the light,
in that blessed purity and holiness. The man who hungers and thirsts after righteousness is the man
who longs for that above everything else. And in the ends that is nothing but a longing to be like
the Lord Jesus Christ Himself. Look at Him; look at His portrait in these Gospels; look at Him
when He was here on earth in His incarnate state; look at Him in His positive obedience to God’s
holy law; look at Him in His reaction to other people, His kindness, His compassion, His sensitive
nature; look at Him in His reaction to His enemies and all that they did to Him. There is the portrait,
and you and I, according to the New Testament doctrine, have been born again and have been fashioned anew
after that pattern and image. The man, therefore, who hungers and thirsts after righteousness, is the
man who wants to be like that. His supreme desire is to be like Christ.
-D. Martyn Lloyd-Jones, Studies in the Sermon on the Mount, pp 66-67
Amen and Amen.