2 Even as You have given Him authority over all mankind (flesh), so that He should give eternal life to all whom You have given to Him.
3 Now this is eternal life, that they should know You, the only true God and Him whom You sent, Jesus Christ.
The foundation of the ministry of Jesus is that the Father had given Him authority.
The word authority is also translated as power. In this verse Jesus is referring to both the authority of God and the power of God, which had been given to Him. These words are also similar to the words of Jesus that precede the Great Commission in Matthew 28.18:
 Jesus came and told His disciples: “I have been given complete authority in Heaven and on earth” – (NLT).
Throughout His ministry He had demonstrated the authority of His Father, through the words of His teaching and the powerful acts displayed in the miracles He performed.
Now, as He faced the cross, He was to demonstrate His complete power and authority over all flesh as He submitted Himself into the hands of men. It may have seemed as though the world had authority over Him, but it was the other way round.
Earlier Jesus had said:
18 no one took it (life) from Me, but I, willingly lay it down. I have authority to lay it down, and I have authority to take it up again. I have received this commandment from My Father – John 10.18.
Pilot obviously thought that He had power and authority over Jesus; however, Jesus told Him:
Then Jesus said: “You would have no power over Me at all unless it were given to you from above. So the one who brought Me to you has the greater sin” – John 19.11 (NLT).
The objective in Jesus being given all authority is very simple and clear: it was to bring eternal life to those whom the Father had given to Jesus.
This is brilliantly summed up in John 3.16:
16 This is the way in which God loved the world: it was so much that He gave His one and only Son, so that everyone who is believing in Him should not be lost, but might have eternal life.
Who are the ones that God has given to Jesus? This verse tells us: it is all those who believe in Jesus as their Lord and Saviour.