1. When we witness Satan loses power. Luke 10:17,18 

2. When we witness Christ gives us power. Luke 10:19

3. When we witness Christ reminds us where to put our Joy. Luke 10:20

4. When we witness we make Christ rejoice. Luke 10:21

Conclusion:

Be a wise child God 

Proverbs 11:30 

The fruit of the righteous is a tree of life; and he that winneth souls is wise. 

Be a Soul winner .

Luke 10:17-21

17 And the seventy returned again with joy, saying, Lord, even the devils are subject unto us through thy name. 18 And he said unto them, I beheld Satan as lightning fall from heaven. 19 Behold, I give unto you power to tread on serpents and scorpions, and over all the power of the enemy:and nothing shall by any means hurt you. 20 Notwithstanding in this rejoice not, that the spirits are subject unto you; but rather rejoice, because your names are written in heaven. 21 In that hour Jesus rejoiced in spirit, and said, I thank thee, O Father, Lord of heaven and earth, that thou hast hid these things from the wise and prudent, and hast revealed them unto babes:even so, Father; for so it seemed good in thy sight