God instills a hunger in our hearts for justification and sanctification. Through the ministry of the Holy Spirit, the unbeliever is drawn by the Father's cords of love and convicted of their sinfulness and need for a Savior. When faith in Christ's sacrificial work is received into the heart, that person is born of the Spirit of God, and a thirsty soul who aches for peace with God is satisfied.
Similarly, God instills a deep hunger in the heart of the Christian. Like Paul, they reach a point in their lives when they, too, cry out to know Christ more intimately. The saved individual begins to learn that salvation is not just the exciting point of rebirth into the family of God but also a journey through life where faith is tried and tested, and God is proved faithful once again. Those who seek Him with their whole heart discover over time that He is the one who satisfies the thirsty soul and calms the troubled breast.
It is not the self-sufficient or self-reliant soul whose hunger is satisfied but the one who yearns for the fullness of Christ. It is not the self-satisfied, independent person or the carnal Christian who finds comfort in the passing pleasures of this fallen world, but the one who prays to the living God. The one who seeks God with his whole heart is the one who finds satisfaction in the Lord. Christ alone is the living water of life, and those who know Him discover Him to be a well of refreshing water that springs up into everlasting life.

Dear Heavenly Father, I come to You today, humbly acknowledging that You alone can satisfy the deepest longing of my soul. I confess that I have sought fulfillment in many things apart from You, only to find myself still hungering and thirsting for more. But Your Word reminds me that You are the One who satisfies the longing soul and fills the hungry soul with goodness. Help me to seek You with my whole heart and to trust in Your goodness and faithfulness. 
In Jesus's name I pray. Amen.