John Calvin Commentary John 6:38

"For I am come down from heaven, not to do mine own will, but the will of him that sent me." — John 6:38 (ASV)

For I came down from heaven. This is a confirmation of the preceding statement: that we do not seek Christ in vain. For faith is a work of God, by which he shows that we are his people and appoints his Son as the protector of our salvation. Now, the Son has no other design than to fulfill the commands of his Father. Consequently, he will never reject those whom his Father has sent. Hence, finally, it follows that faith will never be useless.

Regarding the distinction Christ makes between his own will and the Father's will, in this respect, he accommodates himself to his hearers. Because the human mind is prone to distrust, we are accustomed to contriving some distinction which produces hesitation. To cut off every pretense for those wicked imaginations, Christ declares that he has been manifested to the world, in order that he may actually ratify what the Father has decreed concerning our salvation.