We agree - Jesus did the work of God on the cross because He was/is both divine and human in His Person.
He did not do our work for us though.
What about Phil 2:12 - with fear and trembling work out your salvation?
You can’t just ignore scripture.
That’s right, we can’t.
“Then said they unto him, What shall we do, that we might work the works of God? Jesus answered and said unto them, This is the work of God, that ye believe on him whom he hath sent.” John 6:28-29
He most certainly did. He's the only one who lived a perfect, sin-free life so that when He died, He was able to pay for our sin and conquer death, something we could not have ever done.
Our death is the wages due for our sin. We could not ever save ourselves, no matter how many and what kind of good works we performed.
Why don't we look at the whole passage in Philippians so we can understand the context of that one snippet you gave: Imitating Christ’s Humility
Philippians 2:1-15
1 If you have any encouragement from being united with Christ, if any comfort from his love, if any fellowship with the Spirit, if any tenderness and compassion, 2 then make my joy complete by being like-minded, having the same love, being one in spirit and purpose. 3 Do nothing out of selfish ambition or vain conceit, but in humility consider others better than yourselves. 4 Each of you should look not only to your own interests, but also to the interests of others. 5 Your attitude should be the same as that of Christ Jesus: 6 Who, being in very nature God, did not consider equality with God something to be grasped, 7 but made himself nothing, taking the very nature of a servant, being made in human likeness. 8 And being found in appearance as a man, he humbled himself and became obedient to death— even death on a cross! 9 Therefore God exalted him to the highest place and gave him the name that is above every name, 10 that at the name of Jesus every knee should bow, in heaven and on earth and under the earth, 11 and every tongue confess that Jesus Christ is Lord, to the glory of God the Father. 12 Therefore, my dear friends, as you have always obeyed—not only in my presence, but now much more in my absence—continue to work out your salvation with fear and trembling, 13 for it is God who works in you to will and to act according to his good purpose. 14 Do everything without complaining or arguing, 15 so that you may become blameless and pure, children of God without fault in a crooked and depraved generation, in which you shine like stars in the universe
I learned that whenever you see the word "therefore" in Scripture, you should ask what is it there for? Paul was reminding the believers at Phillipi how they should treat each other in light of the great things that Jesus did for us when he - who was Almighty God - humbled himself to take on flesh and subject himself to the indignities of the cross so that we could be reconciled to God. He took on the form of a servant and then God exalted him above all things that every knee would bow to him and every tongue would confess that Jesus Christ was Lord. Our attitude should be the same, becoming servants for the cause of Christ.
THEREFORE, he told them, just as they had behaved while he was in their presence so should they always strive to live holy and obedient lives and continue to "work out" the salvation that they had been given through their faith in Christ with "fear an trembling". The words "work out" in Greek is katergazomai and means:
1) to perform, accomplish, achieve
2) to work out i.e. to do that from which something results
a) of things: bring about, result in
3) to fashion i.e. render one fit for a thing
If, as you seem to suggest, Paul is telling them to work FOR their salvation, then not only does the verse not say that, but he would be contradicting himself as well as Jesus and Peter and the other Scriptures. We cannot work for our salvation because then it wouldn't be grace. Grace is undeserved mercy and it would be canceled if any of our work was required because then it wouldn't be grace anymore. When we "work out" our salvation, we are exercising it, demonstrating it to the glory of God. In "fear" and "trembling" simply means respect, reverance and "trembling" from tromos used to describe the anxiety of one who distrusts his ability completely to meet all requirements, but religiously does his utmost to fulfil his duty.
Lastly, look what he said after that, "13 for it is God who works in you to will and to act in order to fulfill his good purpose.". Don't leave out that very important part. God works IN us, through the indwelling Holy Spirit to fulfill his will, his good purposes. We cannot ever earn or merit eternal life simply because none of that can pay for sins. It is only through Jesus that we can have our sins satisfactorily paid for and God gifts to us eternal life when we receive his gift by faith.