The Church is the Body of Christ

Eph. 1.20...(God) raised him (Christ) from the dead, and set him at his own right hand in the heavenly places,
21  Far above all principality, and power, and might, and dominion, and every name that is named, not only in this world, but also in that which is to come:
22  And hath put all things under his feet, and gave him to be the head over all things to the church,
23  Which is his body, the fulness of him that filleth all in all.

Eph. 4.11  And he gave some, apostles; and some, prophets; and some, evangelists; and some, pastors and teachers;
12  For the perfecting of the saints, for the work of the ministry, for the edifying of the body of Christ:
13  Till we all come in the unity of the faith, and of the knowledge of the Son of God, unto a perfect man, unto the measure of the stature of the fulness of Christ:
14  That we henceforth be no more children, tossed to and fro, and carried about with every wind of doctrine, by the sleight of men, and cunning craftiness, whereby they lie in wait to deceive;
15  But speaking the truth in love, may grow up into him in all things, which is the head, even Christ:
16  From whom the whole body fitly joined together and compacted by that which every joint supplieth, according to the effectual working in the measure of every part, maketh increase of the body unto the edifying of itself in love.

All things are under the feet of Christ, and the Church is the Body of Christ, and the Body includes the feet, thus God has placed all under the Church, with Christ as the Head.

To what else does Christ give this authority?

Christ placed apostles in His Church (Body), prophets, evangelists, pastors, and teachers.  What other body or group did He give these offices to?  If you said, "None", you are correct.  It is only His Body that He does His work through.  He does not work through the lost--He works through the saved, and the saved are His Body.  If you have ever read, or heard, even one Scripture, you have been touched by the Body of Christ.

I Cor. 12.8  For to one is given by the Spirit the word of wisdom; to another the word of knowledge by the same Spirit;
9  To another faith by the same Spirit; to another the gifts of healing by the same Spirit;
10  To another the working of miracles; to another prophecy; to another discerning of spirits; to another divers kinds of tongues; to another the interpretation of tongues:
11  But all these worketh that one and the selfsame Spirit, dividing to every man severally (individually)as he will.
12  For as the body is one, and hath many members, and all the members of that one body, being many, are one body: so also is Christ.
13  For by one Spirit are we all baptized into one body, whether we be Jews or Gentiles, whether we be bond or free; and have been all made to drink into one Spirit.
14  For the body is not one member, but many.
15  If the foot shall say, Because I am not the hand, I am not of the body; is it therefore not of the body?
16  And if the ear shall say, Because I am not the eye, I am not of the body; is it therefore not of the body?
17  If the whole body were an eye, where were the hearing? If the whole were hearing, where were the smelling?
18  But now hath God set the members every one of them in the body, as it hath pleased him.
19  And if they were all one member, where were the body?
20  But now are they many members, yet but one body.

Through the Holy Spirit, the Church (Body) is given the gifts of the Spirit.  To whom has the Holy Spirit given the spiritual gifts, except to the Body (the Church)?  If you answered, "None", you answered correctly.  It is only His Body that He does His work through.  He does not work through the lost--He works through the saved, and the saved are His Body.  If you have ever been witnessed to, or had one Scripture quoted to you, you have been touched by the Body of Christ, for it is the Body that has preserved His Word, per His direction, for two millennia.