R' Chiya bar Abba said in the name of R' Yochanan: What is the meaning of that which is written (Mishlei 27:18), "He who guards the fig tree shall eat from its fruit?" Why are the words of Torah likened to a fig tree? Just as a fig tree - every time one handles it, he finds more ripe figs (the fruits of a fig tree ripen at staggered intervals), so too with the words of the Torah, every time a person studies them he finds in them new flavour. (Gemara Eiruvin 54b)
In his preface to Pe-as Shulchan, R' Yisrael Shklover writes of his master and teacher, the Gaon of Vilna, "He reviewed all of Talmud Bavli every month. His toil in the study of the holy Torah defies description. He would review each chapter and masechta (tractate) hundreds, and even thousands of times. Out of immense love for the holy Torah, he once spent a long winter night reviewing over and over a single Mishnah in Seder Taharos."
Read full article: http://www.torah.org/learning/olas-shabbos/5758/vaeschanan.html#
Chadrei Chadarim has an article about a sign that was recently erected next to a gravestone of a man who was niftar many years ago. In his will, Rabbi Eliezer Yoseph Lederberg requested that the words that he learned Mesechtot "Beitza" and "Rosh Hashana" over 4000 times should be engraved on his gravestone to perhaps inspire others to do the same. The sign was put up not long ago so that people should take notice.
A talmid of Rav Nosson Tzvi Finkel ztl describes the Rabbi's love for Torah.
One thing in particular that I shall remember about his love for learning was his reaction to the d'var Torah I once said to him. A few years ago during the Lebanon War, in order to encourage the talmidim to continue learning with the same vigour, he requested that we prepare a d'var Torah with our own novel ideas from the books we were studying, eventually to be compiled together in a book. I was so inspired from this ordeal that I felt that I wanted to give him some nachas, just as a child wants to give a parent, and so I decided to tell him my d'var Torah. He listened attentively, as if this were the first time he had ever heard such things, and then at the end he grinned from ear to ear and said 'emes', meaning, 'what you have said is true'. It didn't matter that he knew it already, every word of Torah from anyone, especially a talmid, was precious and exciting to him.