Passage
Let Israel now say, That his lovingkindness [endureth] for ever.
Let Israel now say, That his lovingkindness [endureth] for ever.
Psalms 118:1 Oh give thanks unto Jehovah; for he is good; For his lovingkindness [endureth] for ever.
Psalms 118:2 Let Israel now say, That his lovingkindness [endureth] for ever.
Psalms 118:3 Let the house of Aaron now say, That his lovingkindness [endureth] for ever.
Psalms 118:4 Let them now that fear Jehovah say, That his lovingkindness [endureth] for ever.
The verse centers on "israel", "lovingkindness", "endureth", and "ever". It is saying that the verse draws attention to "israel" and "lovingkindness", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 1's "Oh give thanks unto Jehovah for he..." into verse 3's "Let the house of Aaron now say...", so "israel" and "lovingkindness" 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 "israel" and "lovingkindness" with trust shaped by these words, not by a vague optimism outside the passage.