John 15:16

Ye did not choose me, but I chose you, and appointed you, that ye should go and bear fruit, and that your fruit should abide; that whatsoever ye shall ask of the Father in my name, he may give it you.

The supernatural nature of the call of the apostles to their God-appointed task is in view here. Their commission to teach all nations did not derive from some voluntary assumption of such an office on their part but was imposed upon them from above by Christ's choice of them for that work.

But I chose you ... Concerning this, Westcott said:

Here (and in John 6:70 and John 13:18) the eleven are regarded as representatives of the Lord in relation to his church, favoring the interpretation (that this is reference to a call of the apostleship). The power of the office of the apostles lay for them in the fact that it was not self chosen.[7]

This passage strongly suggests the great commission (Matthew 28:18-20) in the mention of Jesus' being perpetually with them to provide whatever might be asked of the Father.