So far, these words suggest that the power that preserves one's spiritual life belongs to Source. My part is "simply" (again, not easy, at least for me) to trust in Spirit's power to do this work. By placing my spiritual life in God's keeping I preserve it.
Preservation is only the beginning. The next words "you will gain" suggest that I will also acquire something. The final word says what, "your soul," which I take to mean my spiritual health and wholeness. It occurred to me that gain can mean to acquire, but it can also mean to increase or strengthen. So not only do I acquire spiritual health by my endurance, but may also grow in it and through it.
My other contribution is trusting, which I have noted is difficult for me and so not insignificant. Realizing that I have "evidence" on which to base that trust makes it easier to do so. By trusting that greater healing and wholeness are possible for me, and acting from that trust, the healing begins and progresses. This is most of what came to me this morning as I pondered these few pithy words.
The last part of lectio divina is meditating on what these words are calling us to do or to become. I think these words call me to grow in faith that God will preserve my precious life and then to allow that preservation to happen. And as a writer and minister I also feel called to share any insights with others, perhaps encouraging them to trust that by faithfully relying on a power greater than themselves, they stand to gain their own souls.