Wow, you have been shown your error in the two original passages. You have been shown how Paul answers Romans 7 with Romans 8 and 9. Now you desperately go to Philippians 2.
So if there is any encouragement in Christ, any comfort from love, any participation in the Spirit, any affection and sympathy, complete my joy by being of the same mind, having the same love, being in full accord and of one mind. Do nothing from selfish ambition or conceit, but in humility count others more significant than yourselves. Let each of you look not only to his own interests, but also to the interests of others. Have this mind among yourselves, which is yours in Christ Jesus, who, though he was in the form of God, did not count equality with God a thing to be grasped, but emptied himself, by taking the form of a servant,being born in the likeness of men. And being found in human form, he humbled himself by becoming obedient to the point of death, even death on a cross.
Therefore God has highly exalted him and bestowed on him the name that is above every name, so that at the name of Jesus every knee should bow, in heaven and on earth and under the earth, and every tongue confess that Jesus Christ is Lord, to the glory of God the Father.
Therefore, my beloved, as you have always obeyed, so now, not only as in my presence but much more in my absence, work out your own salvation with fear and trembling, for it is God who works in you, both to will and to work for his good pleasure.
~ Philippians 2:1-13
What are the therefore's there for? Make the connections.
The fear and trembling is not because a person can lose there salvation. Paul has told us that there is encouragement in Christ. We draw out what our salvation means, with fear and trembling, because we are in the presence of the holy God who created all things. It is an awesome thing to be in the presence of God. Look at Isaiah's response:
Isaiah 6:1-7
In the year that King Uzziah died I saw the Lord sitting upon a throne, high and lifted up; and the train of his robe filled the temple. Above him stood the seraphim. Each had six wings: with two he covered his face, and with two he covered his feet, and with two he flew. And one called to another and said: “Holy, holy, holy is the Lord of hosts; the whole earth is full of his glory!” And the foundations of the thresholds shook at the voice of him who called, and the house was filled with smoke. And I said: “Woe is me! For I am lost; for I am a man of unclean lips, and I dwell in the midst of a people of unclean lips; for my eyes have seen the King, the Lord of hosts!” Then one of the seraphim flew to me, having in his hand a burning coal that he had taken with tongs from the altar. And he touched my mouth and said: “Behold, this has touched your lips; your guilt is taken away, and your sin atoned for.”
We work out that salvation, which God has gloriously accomplished, with genuine fear and trembling, precisely because we are in the holy presence of God.