The abstract noun "practice" here refers to a way of atoning for sins. Stopping doing it is spoken of as if it were an object that could be taken away. Starting the second way of atoning for sins is spoken of as establishing that practice. Alternate translation: "He stops people atoning for sins the first way in order to atone for sins the second way" (See: [[rc://en/ta/man/jit/figs-abstractnouns]] and [[rc://en/ta/man/jit/figs-metaphor]])
The words "first" and "second" are ordinal numbers. Alternate translation: "old practice ... the new practice" (See: [[rc://en/ta/man/jit/translate-ordinal]])