Strength

"Not by might nor by power, but by My Spirit, says the Lord of Hosts." 

                                                                                 Zechariah 4:6

The work of God isn't done merely by will. Its execution depends on the constant offering of self sacrifice. Only then can the Holy Spirit work in calling, choosing and using His servants. Offering is an example of this: if a servant isn't willing to sacrifice the best that he has - financially speaking - then how will he be able to do it through spiritual service?