Charles Ellicott Commentary 1 Samuel 1:7

"And [as] he did so year by year, when she went up to the house of Jehovah, so she provoked her; therefore she wept, and did not eat." — 1 Samuel 1:7 (ASV)

And as he did so year by year. — That is, Elkanah, on the occasion of every yearly visit to the national sanctuary, was in the habit of publicly giving the childless Hannah the double gift to show his undiminished love. The happier mother of his children, jealous of her rival, every year chose this solemn occasion of offering thank-offerings before the Tabernacle, especially to taunt the childless wife. She no doubt attributed the absence of children, which among the mothers of Israel was considered so deep a calamity, to the special anger of God.