Shovavim
The primary purifications of Shovavim are saying Tehillim and learning Torah. Tana d'Bei Eliyahu (Rabba 18) states, "Come and see the great power of Torah study. It purifies Bnei Yisrael even if they worshipped avodah zarah."
It states ואלה שמות בני ישראל הבאים מצרימה את יעקב איש וביתו באו, "These are the names of Bnei Yisrael coming to Mitzrayim. Yaakov and his household came." Coming and came (באו – הבאים) are present and past tense. Why does the Torah change the tense in the same pasuk?
The Chasam Sofer (Toras Moshe) answers that את יעקב איש וביתו באו implies that Yaakov took his household, together with the air and holy atmosphere of Eretz Yisrael, and transported it to Mitzrayim. They started a yeshiva in Mitzrayim, and it was as if they were living in Eretz Yisrael. However (1:7) it states וימת יוסף וכל אחיו וכל הדור ההוא ובני ישראל פרו וישרצו וירבו ויעצמו במאד מאד ותמלא הארץ אותם, "Yosef, his brothers, and the entire generation were niftar, and the Jewish nation increased and multiplied...and they filled the land." The Midrash (Yalkut Shimoni, Shemos 1) explains that the Jewish nation filled the circuses and the theatres. They stopped studying Torah and were enjoying the Egyptian culture. Therefore, it states הבאים מצרימה, in the present tense. Previously, they weren't really living in Mitzrayim, but now they arrived.
Parashas Shemos starts with the words ואלה שמות בני ישראל הבאים, and the final letters spell תהלים. This hints that saying Tehillim purifies us in Shovavim.
