In Rom 8:26 Paul says the Spirit intercedes “for the saints according to the will of God.”

If we look at the immediate context, along with other scriptures, a case can be made this is a reference to Jesus (who is our intercessor, I.e., mediator, as we all know).

For example, Paul equates the Spirit of God with the Spirit of Christ (Rom 8:9), i.e., “the one who searches our hearts” (Rom 8:27).

Cp. Rev 2:23 where John says the Son of God is “he who searches hearts and minds”.

These statements are a fulfillment of what Jesus himself had promised the Apostles before his death and ascension to the Father in John 14 and 16.

John 14:16

“And I will ask the Father, and he shall give you another parakletos.”

• The parakletos another name for the HS;
• The Greek word translated “another” allos “another (of the same kind)” and not “another (of a different kind),” heteros.

John 14:26

“The parakletos, the holy spirit, whom the Father will send in my name, he will teach you.”

John 16:7

“If I do not go away the parakletos will not come to you.”

The clear implication is of Jesus now identified as the paraclete, as both John and Paul later reveal.

1 Corinthians 15:45 ESV

Thus it is written, “The first man Adam became a living being”; the last Adam became a life-giving spirit.

1 John 2:1

My little children, I write these things to you so that you may not sin.

If anyone sins, we have a Counselor/Advocate with the Father, Jesus Christ, the righteous.

The NET Bible comment on 1 John 2:1 summarizes these scriptures well:

“The reader should have been prepared for this interchangeability of terminology, however, by John 14:16, where Jesus told the disciples that he would ask the Father to send them another paraclete (allos, another of the same kind).

The concept of Jesus’ intercession on behalf of believers does occur elsewhere in the NT, notably in Rom 8:34 and Heb 7:25.”

Heb 7.25

Therefore He is able to save completely those who draw near to God through Him, since He always lives to intercede for them.

Rom 8:34b

Christ Jesus is the one who died—more than that, who was raised—who is at the right hand of God, who indeed is interceding for us.

NOTE: both verses use the same Greek word used in Rom 8.27 to describe how Jesus in the spirit “intercedes for the saints according to the will of God.”

These are all echoes of the so-called Servant Songs in Isa 52-53, specifically Isa 53.12, New Heart English Bible

Therefore I will divide him a portion with the great, and he will divide the spoil with the strong; because he poured out his soul to death, and he was numbered with transgressors; yet he bore the sins of many, and made intercession for their transgressions.