2 Samuel 24:18 KJV

And Gad came that day to David, and said unto him, Go up, rear an altar unto the LORD in the threshingfloor of Araunah the Jebusite.

David's sacrifice, The plague removedGod's encouraging us to offer to him spiritual sacrifices, is an evidence of his reconciling us to himself. David purchased the ground to build the altar....

2 Samuel 24:11 For when David was up in the morning, the word of the LORD came unto the prophet Gad, David's seer, saying,
1 Chronicles 21:18–30 Then the angel of the LORD commanded Gad to say to David, that David should go up, and set up an altar unto the LORD in the threshingfloor of Ornan the Jebusite. …

From OpenBible.info, most relevant first.

Altar Built by David
Araunah A Jebusite from whom David bought a site for an altar
David Takes the military strength of Israel without divine authority, and is reproved
Gad Bids David build an altar on the threshing floor of Ornan
Jerusalem David purchases and erects an altar upon Araunah’s threshing floor
Ornan Called ARAUNAH
Plague On account of David’s sin
Threshing Floor of Araunah purchased by David for a place of sacrifice

GadFortune; luck. (1.) Jacob’s seventh son, by Zilpah, Leah’s handmaid, and the brother of Asher (Gen 30:11–13; Gen 46:16, Gen 46:18). In...
DavidBeloved, the eighth and youngest son of Jesse, a citizen of Bethlehem. His father seems to have been a man in humble life. His mother’s...
LordThere are various Hebrew and Greek words so rendered.
AraunahAgile; also called Ornan 1 Chr 21:15, a Jebusite who dwelt in Jerusalem before it was taken by the Israelites. The destroying angel, sent...

And Gad גָד gād גָּד Proper name
came וַיָּבֹא wayyābōʾ בּוֹא Verb · qal sequential imperfect, third person masculine singular · with and
that day בַּיּוֹם bayyôm יוֹם Noun · masculine singular · with preposition with the
to David דָּוִד dāwid דָּוִד Proper name
and said וַיֹּאמֶר wayyōʾmer אָמַר Verb · qal sequential imperfect, third person masculine singular · with and
unto him, Go up אֶל ʾel Preposition הַהוּא hahûʾ Pronoun · third person masculine singular · with the לוֹ lô Preposition · with suffix: third person masculine singular עֲלֵה ʿălê עָלָה Verb · qal imperative, second person masculine singular
rear הָקֵם hāqēm קוּם Verb · hiphil imperative, second person masculine singular
an altar מִזְבֵּחַ mizbēaḥ מִזְבֵּחַ Noun · masculine singular
unto the LORD לַיהוָה layhwh יְהֹוָה Proper name · with preposition
in the threshingfloor בְּגֹרֶן bĕgōren גֹּרֶן Noun · masculine or feminine singular construct · with preposition
of Araunah אֲרַוְנָה ʾărawnâ אֲרַוְנָה Proper name
the Jebusite הַיְבֻסִי haybusî יְבוּסִי Noun · masculine singular · with the

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