Genesis 50:21

וידבר אל לבם means HE SPOKE words that found ready entrance INTO THEIR HEART: Before you came down hither people spread rumours about me that I was born a slave; through you it became public that I am a free-man by birth. If I were to kill you what would people say? “He saw a party of fine young men and he prided himself on his relationship with them, saying “These are my brothers”, but afterwards he killed them. Have you ever heard of a man killing his brothers?!” (Genesis Rabbah 100:9) Another interpretation is: He said to them, “Ten lights could not extinguish one light; how, then, can one light extinguish ten lights?” (Megillah 16b).

וְעַתָּה֙ אַל־תִּירָ֔אוּ אָנֹכִ֛י אֲכַלְכֵּ֥ל אֶתְכֶ֖ם וְאֶֽת־טַפְּכֶ֑ם וַיְנַחֵ֣ם אוֹתָ֔ם וַיְדַבֵּ֖ר עַל־לִבָּֽם׃

Now therefore fear not: I will nourish you, and your little ones. And he comforted them, and spoke kindly to them.