John Wesley on 1 Samuel 1:10

Bitterness - That is, oppressed with grief. Prayed unto the Lord - They had newly offered their peace - offerings, to obtain the favour of God, and in token of their communion with him, they had feasted upon the sacrifice: and now it was proper to put up her prayer, in virtue of the sacrifice. For the peace - offerings typified Christ's mediation, as well as the sin - offerings: since by this not only atonement is made for sin, but an answer to our prayers obtained.