And they sung together hymns, and praise to the Lord: because he is good, for his mercy endureth for ever towards Israel. And all the people shouted with a great shout, praising the Lord, because the foundations of the temple of the Lord were laid.
Ezra 3:9 Then Josue and his sons and his brethren, Cedmihel, and his sons, and the children of Juda, as one man, stood to hasten them that did the work in the temple of God: the sons of Henadad, and their sons, and their brethren the Levites.
Ezra 3:10 And when the masons laid the foundations of the temple of the Lord, the priests stood in their ornaments with trumpets: and the Levites the sons of Asaph with cymbals, to praise God by the hands of David king of Israel.
Ezra 3:11 And they sung together hymns, and praise to the Lord: because he is good, for his mercy endureth for ever towards Israel. And all the people shouted with a great shout, praising the Lord, because the foundations of the temple of the Lord were laid.
Ezra 3:12 But many of the priests and the Levites, and the chief of the fathers and the ancients that had seen the former temple; when they had the foundation of this temple before their eyes, wept with a loud voice: and many shouting for joy, lifted up their voice.
Ezra 3:13 So that one could not distinguish the voice of the shout of joy, from the noise of the weeping of the people: for one with another the people shouted with a loud shout, and the voice was heard afar off.
The verse centers on "mercy", "sung", "together", "hymns", "praise", "lord", "good", and "endureth". It is saying that the verse draws attention to "mercy" and "sung", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 10's "And when the masons laid the foundations..." into verse 12's "But many of the priests and the...", so "mercy" and "sung" belong inside that flow. In Ezra context, the local focus is covenant, worship, and faithfulness.
A plain takeaway is to answer the verse's own emphasis on "mercy" and "sung" with trust shaped by these words, not by a vague optimism outside the passage.