I Chronicles 6:13 Midrash

וּבְנֵ֧י שְׁמוּאֵ֛ל הַבְּכֹ֥ר וַשְׁנִ֖י וַאֲבִיָּֽה׃ (ס)

And the sons of Samuel: the first-born Vashni; then Abiah.

Read midrashic interpretation of I Chronicles 6:13: and classical rabbinic exegesis.