SP_HELPTEXT system stored procedure is mostly used to check the object definition like definition of a user-defined rule, default, unencrypted Transact-SQL stored procedure, function, trigger, computed column, CHECK constraint, view, or system object such as a system stored procedure.
OBJECT_DEFINITION – is BUILT IN function returns the source text of the specified object. It returns the definition of check constraint, default constraint, stored procedure, function, rule and views.
EXEC sp_helptext 'Procedure Name'
select object_definition(object_id('procedure name')) go
select [definition] from sys.sql_modules where object_id = object_id('procedure name') go