The psalmist is at peace and resolved to tremble at God’s word — not the princes of his day — and to take his joy in the promises of God — not the strength that comes from association with powers — and to love God’s law — not falsehood. So, in 119:165 the psalmist announces his discovery:
Great peace have those who love your law;
nothing can make them stumble.
Shalom rav — great peace. He’s found it. He lives in it. He knows it. In spite of the world around him, he has found God’s great peace. Those who love (ahev) the Torah find great peace.
The image is slightly shifted: those who have this great peace cannot stumble because their steps are guided by the Torah that guides into the good ways of God.
Those whose lives are resolved toward God’s word and promises and Torah discover that their resolution finds peace. These folks aren’t wondering what to do; they know what to God wills. They find that peaceful.