What does Jesus mean when He says anyone who believes in Him will have "living water" flowing out of the center of his heart? In the Old Testament, God is called the fountain of life (Psalm 36:9) and the fountain of living water (Jeremiah 17:13). God's grace is signified by water because of its purity and cleanness. The motion of living water indicates continuous nourishment and comfort, just as God's everlasting love. When we have "rivers of living water" running through us, we have received the Holy Spirit, who has the power to purify all sins, refresh our souls, and keep us alive physically and spiritually. 
In John 4:14, Jesus teaches us that whoever drinks the water He provides will never thirst; it will become a spring of water welling up to eternal life. In this verse, He uses the "living water" to refer to the Holy Spirit, who will be given to everyone believing in Him. These two verses confirm that life after death is only possible through the Holy Spirit. When we put our trust in the Lord and believe Him as our Savior, He will fill our bodies, our hearts, and our souls with the Holy Spirit, and the Holy Spirit will lead us to eternal life. 
There is more than enough water in God's well for everyone, but the pump is only activated by faith. Jesus, the source of Living Water, has extended an invitation to all who thirst. Go and drink! God's grace is free for everyone.

Dear Heavenly Father, Your river of living water never dries up. Overflow me with Your refreshing living water for I am thirsty for your love and grace. Thank You for saving me through Jesus, and for sustaining and renewing me through the Holy Spirit. Bless me with Your wisdom as I seek to draw closer to You and restore my soul with the refreshing living water of Your Holy Spirit. 
In Jesus's name I pray. Amen.