Jesus is the greatest intercessor of all.  From the passages I have copied at the end, we see the following three things that intercession is:

Intercession is praying on the behalf of others whom God has given us. In John 17:9 Jesus prays, “I ask on their behalf, I do not ask on behalf of the world, but of those whom Thou hast given to me.” And those whom were given to Him were not only His close disciples but they were all those who believe (v. 20). And so, we—you and I—are on that list.  And He is still praying for us, since He ever lives to make intercession (Hebrews 7:25).  This means that Jesus has interceded for believers everywhere, in all time throughout history.  What a marvelous thought.

And we are His followers. And so, we must do as He does.  We have that same calling: to intercede for all believers—that they would be unified together with God, kept from the evil one, and sanctified in the truth (Jn. 17).

Intercession is unselfish prayer; it is prayer that includes all believers. Jesus was always interceding for others. He taught that even when we pray for ourselves we should include the rest of the church.  He said, “pray in this way: Our Father…give us…forgive us…as we…deliver us” (Matt. 6:9-13).

Intercession is asking God to forgive others of their sins. Even when facing death He interceded for others as He prayed, “Father forgive them” (Lu. 23:34).

Matthew 6:5-13

“And when you pray, do not be like the hypocrites, for they love to pray standing in the synagogues and on the street corners to be seen by men. I tell you the truth, they have received their reward in full. 6 But when you pray, go into your room, close the door and pray to your Father, who is unseen. Then your Father, who sees what is done in secret, will reward you. 7 And when you pray, do not keep on babbling like pagans, for they think they will be heard because of their many words. 8 Do not be like them, for your Father knows what you need before you ask him.

“This, then, is how you should pray:

“‘Our Father in heaven,

hallowed be your name,

10 your kingdom come,

your will be done

on earth as it is in heaven.

11 Give us today our daily bread.

12 Forgive us our debts,

as we also have forgiven our debtors.

13 And lead us not into temptation,

but deliver us from the evil one.’

Luke 23:34

Jesus said, “Father, forgive them, for they do not know what they are doing.”

John 17

After Jesus said this, he looked toward heaven and prayed:

“Father, the time has come. Glorify your Son, that your Son may glorify you. 2 For you granted him authority over all people that he might give eternal life to all those you have given him. 3 Now this is eternal life: that they may know you, the only true God, and Jesus Christ, whom you have sent. 4 I have brought you glory on earth by completing the work you gave me to do. 5 And now, Father, glorify me in your presence with the glory I had with you before the world began.

6 “I have revealed you to those whom you gave me out of the world. They were yours; you gave them to me and they have obeyed your word. 7 Now they know that everything you have given me comes from you. 8 For I gave them the words you gave me and they accepted them. They knew with certainty that I came from you, and they believed that you sent me. 9 I pray for them. I am not praying for the world, but for those you have given me, for they are yours. 10 All I have is yours, and all you have is mine. And glory has come to me through them. 11 I will remain in the world no longer, but they are still in the world, and I am coming to you. Holy Father, protect them by the power of your name — the name you gave me — so that they may be one as we are one. 12 While I was with them, I protected them and kept them safe by that name you gave me. None has been lost except the one doomed to destruction so that Scripture would be fulfilled.

13 “I am coming to you now, but I say these things while I am still in the world, so that they may have the full measure of my joy within them. 14 I have given them your word and the world has hated them, for they are not of the world any more than I am of the world. 15 My prayer is not that you take them out of the world but that you protect them from the evil one. 16 They are not of the world, even as I am not of it. 17 Sanctify them by the truth; your word is truth. 18 As you sent me into the world, I have sent them into the world. 19 For them I sanctify myself, that they too may be truly sanctified.

20 “My prayer is not for them alone. I pray also for those who will believe in me through their message, 21 that all of them may be one, Father, just as you are in me and I am in you. May they also be in us so that the world may believe that you have sent me. 22 I have given them the glory that you gave me, that they may be one as we are one: 23 I in them and you in me. May they be brought to complete unity to let the world know that you sent me and have loved them even as you have loved me.

24 “Father, I want those you have given me to be with me where I am, and to see my glory, the glory you have given me because you loved me before the creation of the world.

25 “Righteous Father, though the world does not know you, I know you, and they know that you have sent me. 26 I have made you known to them, and will continue to make you known in order that the love you have for me may be in them and that I myself may be in them.”

Hebrews 7:25

Therefore he is able to save completely those who come to God through him, because he always lives to intercede for them.