Summary: What does the shaking off the dust represent ? It speaks of being ready to share the gospel, not covered in the dust of the world.
Earlier the 12 were sent forth with a similar mission (Luke 9:1-6 (quickview) ). 12 is the number of the 12 Tribes of Israel and the sending of the twelve is to Israel alone . 70 is the number of nations mentioned in Genesis 10 (quickview)  and so symbolically the sending of the 70 talks of reaching all nations (Matt 24:14 (quickview) ).
Interestingly there were 12 springs and 70 trees in Elim (Numbers 33:9 (quickview) ) - we are to be as an oasis in the desert to the nations - that they may come free from the dust that covers and come to eat and drink the goodness of the Lord.
The disciples were sent to free the people from the dust of the world (See 1 Cor 15:47- 49). But as they ministered closely with the people they were covered in the dust of the city (literally it says the dust stuck to them like glue). This represented the heaviness, the spiritual environment of the City itself. It was only by a pro-active ’shaking off’ of the dust they could continue (See verse 11).
(2) WHAT IS THE DUST ?
It is possible for us to be covered in the dust of the world. Four main things that dust can represent are (and they spell out DUST)....
(a) Discouragement -
(b) Unforgiveness -
(c) Stress -
(d) Tribulation -
(3) RESULTS OF SHAKING OFF THE DUST:
If we recognise that we have been covered by any of the above ’dusts’ we must rise up and shake it off. Otherwise we will not complete the mission He has given us to reach all nations for Him.
From scripture , we see that each time the Disciples ’shook off the dust’ there was an infilling of the joy of the Holy Spirit (See Luke 10:17 (quickview)  and Acts 13:51-52 (quickview) ).
(4) DISCUSSION QUESTIONS:
What does this mean for us today ?
2. Can you think of any other ’dusts’ that may cling to us (other than the four mentioned) that can hinder us in evangelism ?
3. Which of the dusts is the MAIN one you find sticking to you ? Give an example of how it effects you. What can you do about it ?
As a group pray for each other and have a ’shaking off the dust session’!