Some commentaries say these Scriptures were of a temporary nature. It is claimed that the authority given to the Seventy was not like that given to the Twelve, and that these served their purpose as Jesus preached in the towns on his way to Jerusalem. Nevertheless, Jesus told the Seventy everything that he told the Twelve (cf. Luke 9:1-10), but in more detail, if not given additional commands. Luke speaks of a plenteous harvest (Luke 10:2) but few laborers to do the work. Approximately one year earlier the Apostles were sent out on a similar mission, but their labor was to cast seed for growth. Now the harvest has come. Time was given for the good seed to bear fruit, and what the fields have yielded must be brought in for the Lord of the harvest.
There are four things that Jesus tells these men. First, they are to pray (v. 2) for the provision of the Lord. Laborers are needed in the Lord’s fields, and prayer is needed to bring in the harvest. I cannot think of harvesting a field without remembering the parable of the Householder who hired laborers to go into his vineyard to harvest his fields (Matthew 20:1-16). He went out at the beginning of the day, about 6 A.M. He went again at the third hour or 9 A.M., at the sixth hour (noon), at the ninth hour (3 P.M.), and finally at the eleventh hour or 5 P.M.
The men in this parable have placed themselves in the position of prayer. They have hopes and seek satisfaction for their needs. The Lord responds to each group of men in his own time. The first group bargained with him, as the would-be followers of Christ did in Luke 9:57-62. They wanted a good deal and would have no relationship with the Lord of the harvest, until certain specific promises were given. The other groups in Matthew, however, entered into a relationship with the Lord of the harvest on the promise that he would be fair. They trusted him. However, since they knew that their labor would not be for a full day, they probably did not expect a full days-wage. Nevertheless, the prayer of faith (trust) brings grace and far more than what one dares to hope, while the prayer for justice yields only what can be expected.
Secondly, the Seventy were told that there would be danger to obey the call of God. Jesus sent them as lambs into the place where wolves dwell. These men went into these towns knowing there would be some trouble. They were involved in a great spiritual battle that involved Satan being cast to the earth (Luke 10:18). The Seventy were lambs in the realm of wolves, and they were to act in character. Lambs do not lash out at people, not even their enemies. Neither can we expect to be treated any differently than Christ our Shepherd and Lord had been treated. Our victory is in his blood (Revelation 12:11) not in compromise or bargaining with the enemy. Jesus is Lord! We must trust him.
Third, the Seventy were not to bargain for their provision, as was done with the Householder in the first hour (6 A.M.), and as the would–be followers of Jesus tried to do in Luke 9:57-62. They were to trust that the Lord would be fair in providing for their necessities. All believers are told to be satisfied with the provision God has set before us.
Finally, the Seventy were to proclaim peace to the city and house they entered. Jesus, perhaps had in mind the local synagogue or even a large home with sufficient room to accommodate visitors. Houses in the New Testament period were used as churches are today. It is, perhaps, in this sense that the word “house” should be understood here, as well. If the son of peace dwells there, if the ruler of the synagogue or householder is a man of God, then the peace of God will remain (Luke 10:6; cf. Luke 9:48 and Matthew 10:40-42). If the enemy of the peace of God dwells there, then the prayer of blessing from the Seventy would return to them (Luke 10:6; cf. Psalm 35:11-18). The Seventy were sent to heal the sick, which can also be understood to mean to minister to the weak or those without strength, proclaiming the Kingdom of God unto them (Luke 10:9). Healing can be physical, emotional or spiritual.
If the messengers of the Gospel were not received, they were told to remember that they were lambs. That is, they shouldn’t quarrel or threaten. Instead, they were told to shake off the dust of that city as a testimony to their enemies and proclaim that the Kingdom of God has come near to that city or that house (cf. Acts 13:26, 40, 46; 28:25-28). What the Lord says concerning the Judgment is not what the evangelist is to proclaim to those who do not receive Christ. We are of a different Spirit (Luke 9:55). Our words are words of peace and Good News, not curses and judgment.
What the world does to us, it has already done to Christ (Luke 10:16) whether good or evil. Nevertheless, we are not the world’s judge, only the Lord’s ministers of reconciliation (2Corinthians 5:18-19). We are commanded to proclaim peace to a rebellious world. The world was judged in Genesis 3, it doesn’t need another judgment from God’s messengers. Jesus took that judgment to the cross, and this is the Good News we have been given to spread over the world. If this message is not received, it would not be appropriate to threaten.
 Jamison, Fausset & Brown, volume 5, Luke 10:1; comparison is made with the seventy in the wilderness (Numbers 11:24-25), believing that because their authority seems to have been temporary, so is Jesus’ sending out the seventy in Luke 10 under his authority, temporary in nature.