Passage
Let the house of Aaron now say that his loving kindness endures forever.
Let the house of Aaron now say that his loving kindness endures forever.
Psalms 118:1 Give thanks to Yahweh, for he is good, for his loving kindness endures forever.
Psalms 118:2 Let Israel now say that his loving kindness endures forever.
Psalms 118:3 Let the house of Aaron now say that his loving kindness endures forever.
Psalms 118:4 Now let those who fear Yahweh say that his loving kindness endures forever.
Psalms 118:5 Out of my distress, I called on Yah. Yah answered me with freedom.
The verse centers on "house", "aaron", "loving", "kindness", "endures", and "forever". It is saying that the verse draws attention to "house" and "aaron", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 2's "Let Israel now say that his loving..." into verse 4's "Now let those who fear Yahweh say...", so "house" and "aaron" 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 "house" and "aaron" with trust shaped by these words, not by a vague optimism outside the passage.