I shall not die, but live. The psalmist speaks, not in his own person, but in the name of his nation. They had been brought very near to extinction; but now the danger was past. God had given them "a reviving" (Ezra 9:8, Ezra 9:9); and they felt that henceforth they would "live."
And declare the works of the Lord. They would employ the new life granted them in "declaring God's works" (see Psalms 40:5, Psalms 40:10; Psalms 96:3; Psalms 145:4-6); i.e. they would witness to all men of "the might of his marvelous acts," and "abundantly utter the memory of his great goodness."