This Beatitude made me think of a hymn by Fanny Crosby:
"He hideth my soul in the cleft of the rock,
That shadows a dry, thirsty land;
He hideth my life in the depths of His love,
And covers me there with His hand."
Hungering and Thirsting are strong words. They don't just mean feeling a "little peckish" or a "tiny bit parched". The words Jesus used meant extremes of these states, they meant earnestly, desperately desiring food and water. They called forth visions of famine. Unless you have been in extreme circumstances, you might never experience this kind of hunger or thirst. That is why I chose the picture above. Try and place yourself in this setting. There is nothing to satisfy your hunger and thirst, the landscape ahead and behind is devoid of any kind of relief. This is what the world looks like to those who "Hunger and Thirst after Righteousness"!
I used to explain to my Sunday school classes that we all have a "God shaped" hole in our heart. It's like a puzzle piece that is missing, and it is such a unique shape that no other piece can fill the space. Our lives aren't complete without God. In one form or another, we seek for our Creator. Some people try and fit other things in the void. They try and fill their lives with friends or wealth, perhaps power or excitement, sometimes they try seeking after all kinds of physical or mental sensations. Nothing satisfies the longing, everything falls short of making them feel completely whole. Those who come to the point, early or late, of realizing that they are lacking God in their lives look at the world like the picture above. King David put it this way: "My soul thirsts for God, for the living God. When can I go and meet with God?" (Psalms 42:2 NIV) In another Psalm he says "You, God, are my God, earnestly I seek you; I thirst for you, my whole being longs for you, in a dry and parched land where there is no water." (Psalm 63:1-2 NIV)
Righteousness is the word that explains why we cannot find God. He requires it and we don't have it. There is nothing in this world or in ourselves that can supply the righteousness that we need in order to approach God. Paul said: "As it is written, There is none righteous, no, not one" (Romans 3:10) In Isaiah we find the clue to our unrighteousness: "All we like sheep have gone astray; we have turned every one to his own way; and the LORD hath laid on him the iniquity of us all". (Isaiah 53:6) We are not sinless, not one of us. Jesus took those sins upon Himself and in doing so He supplied us with what we lack: "God made Him who had no sin to be sin for us, so that in Him we might become the righteousness of God." (2 Corinthians 5:21NIV). So, when you are Hungering and Thirsting for the Righteousness you need in order to have a relationship with God, you need look no farther than God's "only begotten Son".
In the fourth Beatitude Jesus promises Happiness to those who Hunger and Thirst after Righteousness. Why? Because they will be filled to overflowing from a never ending source. Your Creator formed you with a need inside yourself to find Him. It's a kind of "homing instinct". God wants you to seek Him and in His love and compassion He gave you a way to do that. Your constant need for Righteousness will be endlessly supplied. In satisfying your need for a righteous relationship with your Creator, you will find a Happiness, a Blessedness that nothing on this earth can provide.