Passage
Thy righteousness is an everlasting righteousness, And thy law is truth.
Thy righteousness is an everlasting righteousness, And thy law is truth.
Psalms 119:140 Thy word is very pure; Therefore thy servant loveth it.
Psalms 119:141 I am small and despised; [Yet] do I not forget thy precepts.
Psalms 119:142 Thy righteousness is an everlasting righteousness, And thy law is truth.
Psalms 119:143 Trouble and anguish have taken hold on me; [Yet] thy commandments are my delight.
Psalms 119:144 Thy testimonies are righteous for ever: Give me understanding, and I shall live. QOPH.
The verse centers on "righteousness", "everlasting", and "truth". It is saying that the verse draws attention to "righteousness" and "everlasting", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 141's "I am small and despised Yet do..." into verse 143's "Trouble and anguish have taken hold on...", so "righteousness" and "everlasting" belong inside that flow. In Psalms context, the local focus is worship, trust, the LORD's kingship, and covenant mercy.
A plain takeaway is to answer the verse's own emphasis on "righteousness" and "everlasting" with trust shaped by these words, not by a vague optimism outside the passage.