If your enemies are starving, feed them some bread;
if they are thirsty, give them water to drink.
By doing this, you will heap burning coals on their heads,
and the Lord will reward you.

The Bible (The Old Testament) (14th - 2nd C BC) Judeo-Christian sacred scripture [Tanakh, Hebrew Bible], incl. the Apocrypha (Deuterocanonicals)

Book 20. Proverbs 25:21ff (Prov 25:21-22) [CEB (2011)]
    (Source)

See Romans 12:19-21.

Alternate translations:

If thine enemy be hungry, give him bread to eat;
and if he be thirsty, give him water to drink:
for thou shalt heap coals of fire upon his head,
and the Lord shall reward thee.
[KJV (1611)]

If your enemy is hungry, give him something to eat; if thirsty, something to drink.
By this you heap red-hot coals on his head, and Yahweh will reward you.
[JB (1966)]

If your enemy is hungry, give him something to eat; if thirsty, something to drink.
By this you will be heaping red-hot coals on his head, and Yahweh will reward you.
[NJB (1985)]

If your enemies are hungry, feed them; if they are thirsty, give them a drink. 22 You will make them burn with shame, and the Lord will reward you.
[GNT (1992 ed.)]

If your enemies are hungry, give them bread to eat,
and if they are thirsty, give them water to drink,
for you will heap coals of fire on their heads,
and the Lord will reward you.
[NRSV (2021 ed.)]

If your enemy is hungry, give him bread to eat;
If he is thirsty, give him water to drink.
You will be heaping live coals on his head,
And God will reward you.
[RJPS (2023 ed.)]