Mascherano said: "Barcelona contacted my agents regarding a possible move.
"But I have always been a professional and have never left a club high and dry, and I was not going to do that this time with Liverpool.
"I will always value the fact Benitez took a chance on me when neither Carlos Tevez nor I were being given chances at West Ham.
"Benitez is someone who is very serious and clear. He spoke with me and told me I was a key player, and that I could not abandon the club just for financial reasons."
Mascherano, who played in Argentina's 3-2 win in Russia in midweek, admits his head was turned by Barca's advances.
But he added: "When Xabi Alonso left for Real Madrid I knew that me also leaving was impossible, but I had already made a commitment with Rafa to stay 100 per cent with the project.
"Last year we were so close to being champions and we'll be back in the title fight again."