Thank you for your reply.
David and Goliath in 1 Samuel 17
David and Jonathan 1 Samuel 18
David and Saul 1 Samuel 19
David and Nabal 1 Samuel 25
David given Ziklag 1 Samuel 27
David mistrusted by the Philistines 1 Samuel 29
David defeats Amalekites 1 Samuel 30
Wealthy sheep-owner Nabal refused to help David. Nabal was very bad according to 1 Samuel 25:2-3; 1 Samuel 25:17; 1 Samuel 25:21; 1 Samuel 25:23-25
Nabal's own men feared how David would react and told, Not David, but told his wife Abigail. As David approached intending to slay Nabal, Abigail persuaded him not to become guilty.
David, although being imperfect, took the sensible advice of Abigail. About ten days later Nabal was struck dead by God - 1 Samuel 25:37-39
Where does it say David prayed against Nabal, or is it someone else you have in mind ?
In the Psalms he prays against people a lot. A prayer of his that I have adopted is his prayer against the people who fed him bile, from Psalms 69:21-28.
Psalm 69:21-28
New International Version (NIV)
(21)They put gall in my food
and gave me vinegar for my thirst.
(22)May the table set before them become a snare;
may it become retribution and a trap.
(23)May their eyes be darkened so they cannot see,
and their backs be bent forever.
(24)Pour out your wrath on them;
let your fierce anger overtake them.
(25)May their place be deserted;
let there be no one to dwell in their tents.
(26)For they persecute those you wound
and talk about the pain of those you hurt.
(27)Charge them with crime upon crime;
do not let them share in your salvation.
(28)May they be blotted out of the book of life
and not be listed with the righteous.