Musa bin Salamah narrates: Sinan bin Salamah instructed me to ask Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) about sea water, and to ask in which part of the month I should fast. I went to Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) and said: My brother has instructed me to ask you about performing ablution with sea water. Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said: There are two seas; whichever of the two you perform ablution with, it will do you no harm. (The narrator asked:) And in which part of the month should I fast? He said: In the Ayyam al-Bid (the white days). I asked: We take part in battles and captives come into our hands; may I free someone on behalf of my mother, even though she did not instruct me to do so? Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said: Free a slave on behalf of your mother.
Imam al-Bazzar recorded this narration, and its narrators are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الطهارة / 1082