Why did Jesus walk all the way to John the Baptist to be baptized? What exactly was the power Christ gave His apostles so they could heal and cast out unclean spirits? Why did Peter and John need to lay their hands on the people to give them the gift of the Holy Ghost?
Authority is the answer. Christ went to John because John, through his lineage, held the priesthood authority to baptize Him. Priesthood authority is what Christ gave to the Apostles, allowing them to heal and cast out spirits. This same authority is what Peter and John used to bestow the gift of the Holy Ghost.
Jesus Christ’s church is His kingdom. I like to think of this as a literal thing, like a medieval times type of thing. God the Father is the ultimate king over all the land. Jesus Christ, being His Only Begotten Son, is the Prince, the rightful heir to the kingdom. His blood is royal blood, and through it He holds the authority to conduct the affairs of the kingdom. This authority can be passed down to us, but only through the proper way.
No one can just say they have the authority. It must be given to them, and they must be called of God. Christ gave this royal authority to His chosen apostles, allowing them to conduct the affairs of The Church, His kingdom.
The apostles were not received well however, and were eventually disposed of. Because of this corruption, the authority was not passed down in the correct way and was lost. But it was restored. The King (God the Father) and the Heir (Jesus Christ) visited a young boy named Joseph Smith. This young boy was called of God and the priesthood authority was given to him by John the Baptist, Peter, James, and John, as resurrected beings.
For centuries, the royal authority was lost, but it has been restored. The Prophet Joseph Smith was called of God, and the authority, the right to officiate in Christ’s church, was restored through him. The Church of Jesus Christ is again on the Earth! The proof is a record known as the Book of Mormon. By reading it, pondering it, and praying about it, you can know if the priesthood authority was restored through Joseph Smith.