I might be indicating the obvious, but I suppose I say this because I myself come from an ethnic group with an Eastern cultural background, therefore, I am somewhat familiar with close affinities between families in the Eastern world.
King David is an Israelite, and more specifically traces his roots to the tribe of Judah, but his Moab ethnic lineage background is also recorded, and there seems to be some affinity expressed between David and the King of Moab because since David was fleeing from King Saul, he decided to ask the King of Moab to look after his parents since he was in exile.
13 So Boaz took Ruth, and she became his wife, and he went in to her. And the Lord [a]enabled her to conceive, and she gave birth to a son. 14 Then the women said to Naomi, “Blessed is the Lord who has not left you without a redeemer today, and may his name [c]become famous in Israel. 15 May he also be to you a restorer of life and a sustainer of your old age; for your daughter-in-law, who loves you and is better to you than seven sons, has given birth to him.” 16 Then Naomi took the child [e]and laid him in her lap, and became his nurse. 17 The neighbor women gave him a name, saying, “A son has been born to Naomi!” So they named him Obed. He is the father of Jesse, the father of David.
1 Samuel 22:1-4
1 So David departed from there and escaped to the cave of Adullam; and when his brothers and all his father’s household heard of it, they went down there to him.......................................... ........................................ 3 And David went from there to Mizpah of Moab; and he said to the king of Moab, “Please let my father and my mother come and stay with you until I know what God will do for me.” 4 Then he left them with the king of Moab; and they stayed with him all the time that David was in the stronghold.
Is 1 Samuel 22:1-4 recorded event of David asking King of Moab to look after his parents since he was in fleeing King Saul does show that David had some kind of affinity to the Moabite ethnic group since his ancestor is Ruth the Moabitess?