In The Children of Húrin:
for Hador was an Elf-friend, and Ulmo, moreover, had counselled Turgon to deal kindly with the sons of that House, from whom help should come to him at need.
In The Silmarillion, “Of the Ruin of Beleriand”:
. . . for messages and dreams had come to him up Sirion from the sea, from Ulmo, Lord of Waters, warning him of woe to come and counselling him to deal kindly with the sons of the house of Hador, from whom help should come to him at need.