So Jesus said, “When you may lift up the Son of Man, then you will know that I am, and I do nothing from myself, but just as the Father taught me, I speak these things. And the one having appointed me is with me. He has not left me alone, in that I myself always do the things pleasing to him.”
When Jesus refers to them lifting up the Son of Man, he could be referring to them lifting him up on the cross – something which some of his hearers were already intent on achieving. He could also be referring to them lifting him up – exalting him – in their hearts after his cross, death and resurrection. Both?
If both apply, then they will be convinced that he is the ‘I am’ – but only after crucifying him. They will know that he is the same as the Most High who, in their Scriptures (the Bible’s Old Testament,) was named the ‘I am who I am.’
Speaking these things himself, many believed into him. So Jesus stated to those Jews believing in him, “If you may stay in my own word you are truly my disciples, and you will know the truth, and the truth will free you.”
Many believe into him. He would love them to ‘stay in [his] own word.’ Only then will they ‘know the truth and the truth will free’ them. Free them?
They answered him, “We are seed of Abraham and enslaved to no-one at any time. How do you state that, ‘You will come to be free’?” Jesus answered them, “Truly, truly I state to you, that everyone doing sin is a slave of sin. In fact the slave does not stay in the household into eternity; the son stays into eternity. So if the son may free you, you will really be free.”
Free them from slavery to self-exalting sin. ‘Sin’ in the singular (as used by him here) means falling short all the time. Self-interest forces us, in our deeds, to fall far short of all we should be. On my own I can’t free myself of that. And it’s that which, enslaving me, stops me being ‘a son’ ‘in the household into eternity.’ I need ‘the son to make me free - indeed.’