When God is doing something through you it makes you feel alive.  Deeds of mercy connect us to the Source of mercy.  The word and works of God are alive.  They make us alive, and you know this aliveness is not you.  You know that Someone is doing something through you and your senses tell you that you are more alive in that moment than at any other.  Life comes from our connectedness to God and practicing His words and His deeds.  

“This is a trustworthy statement; and concerning these things I want you to speak confidently, so that those who have believed God will be careful to engage in good deeds. These things are good and profitable for men.” Titus 3:8 (NASB)