One of the types of righteousness for which we are to hunger and thirst is the one that occupies the greater portion of our life after conversion. Notice how Jesus states this beatitude. He does not say, "Blessed are those who have hungered . . . ," but rather, "Blessed are those who hunger [do hunger, KJV]." This hungering and thirsting is a continuous state, and it must be this way for the second kind of righteousness, elsewhere called pursuing holiness, going on to perfection, or growing in the grace and the knowledge of Jesus Christ. Frequently the Bible calls it sanctification. None of these terms is specifically righteousness, but all are contained within its broad meaning. This righteousness is created in us, imparted to us by God's Holy Spirit following justification as we experience our relationship with God. It is seeking godly character to be prepared for living in His Kingdom.
God cannot create His holy and righteous character by fiat. It requires the willing and freely given cooperation of the called; by exercising their free moral agency, they submit to Him in the experiences of life. Submission is difficult, and thus Christianity is no cake-walk through a garden. Jesus often warns that it will require a devotion to Him of such degree that all else must be secondary to Him. We are to bear our crosses and count the cost (Luke 14:26-28). He also warns, "The way is difficult and narrow" (Matthew 7:14), and "He who endures to the end shall be saved" (Matthew 24:13). The trek of the ancient Israelites through the wilderness is a type of the Christian's pilgrimage to the Kingdom of God. Their wilderness experiences expose a number of pitfalls that can destroy a Christian's faith and enthusiasm for continuing to the end.
Through this beatitude, God presents us with a serious challenge. Because it is continuously needed, it establishes a demanding requirement. How much do we want goodness, the righteousness of God? Do we want it as much as a starving man desires food or a parched man wants water? Do we so lack vision that we will give up our faith as all the Israelites, save Joshua and Caleb, did in the wilderness? According to Hebrews 4:1, though they heard the good news, they did not believe it sufficiently. They, therefore, died in the wilderness, their pilgrimage finished before they reached their goal. Rather than submit, they resisted God until their deaths. Apparently, they did not hunger for it.
Most of us have a desire for God's Kingdom and His righteousness, but it is, to our detriment, frequently nebulous rather than sharp. When the time comes to make a choice, we are not prepared to make the required effort or sacrifice that the righteousness of God demands. It is situations like these that reveal that we do not desire righteousness more than anything else.