Do anything for Christ out of love and gratitude
All those who loved Christ and responded  to His love were wounded by God’s love, His concern and condescension.   God’s generosity and bounty to man were such that He made man worthy of  becoming like to God. The hearts of the saints were incurably wounded  in the sense that love, desire and attraction towards God were planted  in all their hearts.
If you are fully aware of who you are  and know that God has called you, while He could have thrown you away,  and, indeed, that He has called you as an equal member, as a coheir of  Christ, then you are captured by this generosity, by this reality and  your soul fills with gratitude. In response to that, you feel inclined  to do anything for Christ with ten times more force than others, who are  worthy, do.