In the Old Testament, the prophets spoke about a remnant among God's people. They spoke about how in a time of spiritual decline among God's people, there would be a few who would remain faithful to God. The theme of the Prophets was restoration.
For example, Hosea spoke about spiritual adultery and God's unchanging love. Habakkuk spoke about the conflict of faith and triumph of faith. Zechariah's burden was the movement of God's people from Babylon to Jerusalem. Haggai's burden was the building up of the temple. Each prophet had a unique burden given to him by God - but all of them were concerned about the lack of holiness among God's people.
Holiness and God's unchanging love were the burden of all the prophets: Holiness in God's people and God's unchanging love for His people even when they are in spiritual adultery and gone astray. God's desire was always to bring His people back. He disciplines them; but then He wants to bring them back to Him after the discipline is over.
This is how true prophetic ministry should function in the church too. A true prophet in the church today will have the same burden that the Old Testament prophets had for holiness among God's people. And He will be moved as they were, by God's unchanging, longsuffering, compassionate love that perpetually desires to bring His backslidden people back to Him and to genuine holiness. There should be a prophetic ministry in every church, if it is to be kept alive and functioning for God as it should.
The burden God lays on your heart is almost always an indication of the ministry He has planned for you. So wait on the Lord to receive a burden from Him. If you serve the Lord without a burden, you will get bored with the Lord's work after a while, and you are likely to end up seeking after money, man's honour or earthly comfort. It is unfortunate that many who claim to be serving the Lord today have no God-given burden for their ministry.
God may give one man a burden to work among children and another a burden for evangelism. Yet another may be given a burden to teach God's people. God gives different burdens to different members of Christ's body. We must not imitate someone else's ministry or try to have his burden. Don't force others to have your burden; and don't allow anyone else to give you his burden. Let God Himself give you a burden - the one He has planned for you.
The more we come into fellowship with God's heart, the more we will share His burden. If God has called you to be an Evangelist, He will give you a compassion for lost souls. If God calls you to be a Teacher, He will give you a compassion for believers who are blinded and deceived, who are not entering into a life of victory. Fellowship with the heart of God in sharing His compassion is essential if we are to fulfil our ministry effectively.
Many people have urged me to have a burden for their particular ministry - usually evangelism. But I have always resisted such pressures. I am not interested in having the burden God has given to another. God has given me a specific burden and I am determined that that is the only ministry I will fulfil. The prophets never allowed anyone to sidetrack them from the burden and the ministry God gave them.
If you don't have any burden at all, you must go to God and ask Him to give you a burden. He has a definite task for you to fulfil in the body of Christ and you must know what it is.
Many preachers wander from one ministry to another - joining whichever Christian organisation offers them the highest salary. For example, they may start with an apparent "burden" for a radio ministry. But if some child-evangelism organization then offers them a higher salary, they suddenly develop a "burden" for child-evangelism! A little later, if a Christian literature organisation offers them a still higher salary, their "burden" suddenly shifts to a literature ministry!! Such preachers are not serving the Lord. They are religious men who are engaged in Babylonian "businesses".
When God gives you a burden, you cannot give that up just because some organisation offered you better earthly benefits.