Hi Liz,
I would take an opposite view from you on the issue. I respectfully disagree and would like to state what I see in the verses that you have quoted in defense of your position. Not to start a spat, but just to give you a perspective on how someone else may see the same verses.
Blessings
>>>>"Romans 8:35-39
Who shall separate us from the love of Christ? Shall trouble or hardship or persecution or famine or nakedness or danger or sword? As it is written: "For your sake we face death all day long; we are considered as sheep to be slaughtered." No, in all these things we are more than conquerors through him who loved us. For I am convinced that neither death nor life, neither angels nor demons, neither the present nor the future, nor any powers, neither height nor depth, nor anything else in all creation, will be able to separate us from the love of God that is in Christ Jesus our Lord."
The context of the verse speaks of the love of Christ for those that are going through intense persecution. Nothing external to the believer can bring separation, even though they may feel that God has forsaken them. There is a universal love of God for mankind, and a love for only those that are in Christ. This passage concerns that later. The passage is dealing with the love of Christ and assurance. However, the context is not dealing with an assurance that says that one cannot ever forsake salvation through Christ. Keep yourselves in the love of God Jude 21.
>>>>"John 10:27-30
My sheep listen to my voice; I know them, and they follow me. I give them eternal life, and they shall never perish; no one can snatch them out of my hand. My Father, who has given them to me, is greater than all; no one can snatch them out of my Father's hand. I and the Father are one."
The sheep are secure and shall never perish. Nothing external to the sheep shall be able to snatch (take by force) them out of the hand of God. The passage also defines the sheep. Only those that are (present tense) hearing, and (present tense) following Jesus are called sheep in this context. Ones that cease to hear (listen) and follow are not His sheep. And a stranger will they not follow, but will flee from him: for they know his voice. Jn. 10:5
>>>"I hear that we can "jump off His hand" I don't believe that. If the angels who are higher then humans cannot separate us from His love, how can we, puny mortals, separate ourselves?"
Angels and principalities are external influences, which the entire context of both verses speak of. If one is free to accept salvation, there is nothing within scripture that says that freedom ceases at that point. If the Son shall make you free, ye shall be free indeed.
>>>> "Hebrews 9:15
For this reason Christ is the mediator of a new covenant, that those who are called may receive the promised eternal inheritance --now that he has died as a ransom to set them free from the sins committed under the first covenant.
The passage says that the inheritance is eternal. It is eternal whether we accept it or reject it. The passage does not say that anyone has an eternal and irrevocable possession of it. The inheritance is eternal, not our possession of it.
>>>> "Ephesians 1:13-14
And you also were included in Christ when you heard the word of truth, the gospel of your salvation. Having believed, you were marked in him with a seal, the promised Holy Spirit, who is a deposit guaranteeing our inheritance until the redemption of those who are God's possession--to the praise of his glory. "
The Holy Spirit is our seal. He is an earnest, a down payment as a guarantee of our inheritance until we actually have our redemption in its fullness. No doubt a glorious promise. Nothing is said in this verse of the possibility the loss of salvation, and equally, the impossibility of losing salvation, that is not the context of the discussion.
>>>> "1 Peter 1:3-5
Praise be to the God and Father of our Lord Jesus Christ! In his great mercy he has given us new birth into a living hope through the resurrection of Jesus Christ from the dead, and into an inheritance that can never perish, spoil or fade --kept in heaven for you, who through faith are shielded by God's power until the coming of the salvation that is ready to be revealed in the last time."
The inheritance that can never perish, spoil or fade which is stated for our hope. It is kept in heaven for you, who are kept by the power of God through faith. Faith is the condition, for, without faith it is impossible to please Him. Heb. 11:6.