Teal'c's words to Tomin about redemption are hard, but comforting. It's appropriate that they come from Teal'c. Once upon a time, Teal'c was in the same position as Tomin: serving a being he thought was a god, and doing terrible things to innocent people, first because he believed it was right, and then later because he thought he had no other choice. Now Tomin knows better, and is filled with remorse. Teal'c understands exactly what the man is going through, and he knows what will comfort and encourage him. He may never be able to make up for the things he's done, but he can still try to make things better.