Does the Bible say that a pastor cannot do any other job to support his family? Are the priests in the Old Testament and pastors in the New Testament the same or not?
There is a big difference between Old Testament priests and New Testament pastors. Priests were men from the Tribe of Levi who served in the Tabernacle in the wilderness and later in the Temple in Jerusalem. This was their full-time job and the other tribes of Israel brought their “tithes and offerings” to the Levitical priests in order to support them. “Behold, I have given the children of Levi all the tithes in Israel as an inheritance in return for the work which they perform, the work of the tabernacle of meeting” (Numbers 18:21). Pastors are men in the church of God who have been given the spiritual gift to “shepherd the flock of God.” The Apostle Paul told a group of pastors in Acts 20:28, “Therefore take heed to yourselves and to all the flock, among which the Holy Spirit has made you overseers, to shepherd the church of God which He purchased with His own blood.” Their call to shepherd the flock is not based on being born in a certain family; it is a Divine calling from Christ in the glory. We see this in Ephesians 4:7-8, 11-12: “But to each one of us was given according to the measure of Christ’s gift. Therefore He says: ‘When He ascended on high, He led captivity captive, and gave gifts to men….And He gave some to be apostles, some prophets, some evangelists, and some PASTORS and teachers, for the equipping of the saints for the work of the ministry, for the edifying of the body of Christ.” We read nothing of them receiving a stipulated salary from other believers, nor are believers commanded to “bring tithes (10% of their income)” to them in order to support them. Yet we shall see that they do deserve support and the Lord provides for their temporal needs through the saints.
As we saw from Ephesians chapter 4, Christ has given certain men as gifts to the church. The “pastor” was one of many gifts that Christ gave in order to “equip the saints for the work of the ministry, for the edifying of the body of Christ.” These “gifted men” could be “full-time servants” who would spend their lives devoted to the special work the Lord called them to do. In that case they would surely need to receive financial support to meet their temporal needs, even if they were single men without a wife and children. Here is what the Apostle Paul wrote on this subject: “Am I not an apostle?…Do we have no right to eat and drink?…Or is it only Barnabas and I who have no right to refrain from working? Who ever goes to war at his own expense? Who plants a vineyard and does not eat of its fruit? Or who tends a flock and does not drink of the milk of the flock?…If we have sown spiritual things for you, is it a great thing if we reap your material things” (1st Corinthians 9:1, 4, 6-7, 11)? Paul is most definitely teaching us that a gifted servant of God (whether that be an apostle, evangelist, pastor or teacher) has every right NOT TO WORK AND TO BE SUPPORTED FINANCIALLY by those to whom they minister the Word to. He ministered to the saints SPIRITUAL THINGS and thus they should minister to him MATERIAL THINGS.
You asked, “Can a pastor do any other job to support his family?” Let’s read what Paul said next in verse 12, “If others are partakers of this right over you, are we not even more? Nevertheless WE HAVE NOT USED THIS RIGHT, but endure all things lest we hinder the gospel of Christ.” Paul had every right to receive financial support from the saints at Corinth but instead of relying on their support we read that he worked as a TENTMAKER while there. “And he (Paul) found a certain Jew named Aquila…with his wife Priscilla…and he came to them. So because he was OF THE SAME TRADE, he stayed with them and WORKED, for by occupation THEY WERE TENTMAKERS” (Acts 18:2-3). You can read of the specific reasons Paul had to support himself at Corinth in verses 13-18 and 2 Corinthians 11:9). So we see that the NORM is that full-time servants of God in the church will be supported by fellow-believers (who give as the Lord leads them with willing and cheerful hearts…see 2 Corinthians 8:12 & 9:6-7), but there may be exceptions where one will be led of the Lord to “work part-time” to provide for his needs. (DO) (535.5)