The answer is: Mercy

1 Chr 16:34; 2 Chr 5:13; 2 Chr 7:3; Ezra 3:11; Psalm 106:1; Psalm 107:1; Psalm 118:1; Psalm 118:29; Psalm 136:1; Jer 33:11

The phrase, "O give thanks unto the Lord; for he is good: for his mercy endureth for ever," resonates throughout Scripture, emphasizing themes of gratitude and Divine compassion we see in various biblical texts. The word "mercy" captures not just a fleeting kindness, but a steadfast loyalty and love that stands the test of time. Throughout the Bible, God's mercy inspires a sense of community and responsibility towards one another, especially in moments of collective reflection like feasts and celebrations.

Notably, this phrase appears multiple times in Psalms, creating a rhythmic echo that invites us to unite in gratitude. Psalm 136, referred to as the "Great Hallel," repeats the theme of enduring mercy through each line, symbolizing how deeply interwoven this idea is into the very fabric of faith and worship tradition.

Moreover, the mention of divine mercy transcends mere commands for thanksgiving; it's a call to remember past exoduses, rescues, and sustainers of hope. When the Israelites rejoiced after rebuilding the altar in Ezra, for example, they reaffirmed their gratefulness for this enduring mercy—much like those today who gather for Thanksgiving. It’s a common thread weaves through context and history, evidencing an unbreakable bond between people and the divine throughout generations. So, as we reflect on this classic phrase, we can echo it in our everyday lives, fostering a spirit of gratitude that reigns throughout the ages!