diff --git a/README.md b/README.md
index f5de6ece..313e4d0e 100644
--- a/README.md
+++ b/README.md
@@ -62,6 +62,7 @@ current_user # Available in views
 redirect_back_or_to # Use when a user tries to access a page while logged out, is asked to login, and we want to return him back to the page he originally wanted
 @user.external? # Users who signed up using Facebook, Twitter, etc.
 @user.active_for_authentication? # Add this method to define behaviour that will prevent selected users from signing in
+User.scope_for_authentication # Define this class method to add additional conditions to search for a user. Helpful for Soft Delete.
 @user.valid_password?('secret') # Compares 'secret' with the actual user's password, returns true if they match
 User.authenticates_with_sorcery!
 ```
diff --git a/lib/sorcery/adapters/active_record_adapter.rb b/lib/sorcery/adapters/active_record_adapter.rb
index dac9facf..87ae8407 100644
--- a/lib/sorcery/adapters/active_record_adapter.rb
+++ b/lib/sorcery/adapters/active_record_adapter.rb
@@ -45,11 +45,11 @@ def find_by_oauth_credentials(provider, uid)
             @user_config.provider_attribute_name     => provider
           }
 
-          @klass.where(conditions).first
+          collection.where(conditions).first
         end
 
         def find_by_remember_me_token(token)
-          @klass.where(@klass.sorcery_config.remember_me_token_attribute_name => token).first
+          collection.where(@klass.sorcery_config.remember_me_token_attribute_name => token).first
         end
 
         def find_by_credentials(credentials)
@@ -69,21 +69,21 @@ def find_by_credentials(credentials)
                        end
           end
 
-          @klass.where(relation).first
+          collection.where(relation).first
         end
 
         def find_by_token(token_attr_name, token)
           condition = @klass.arel_table[token_attr_name].eq(token)
 
-          @klass.where(condition).first
+          collection.where(condition).first
         end
 
         def find_by_activation_token(token)
-          @klass.where(@klass.sorcery_config.activation_token_attribute_name => token).first
+          collection.where(@klass.sorcery_config.activation_token_attribute_name => token).first
         end
 
         def find_by_id(id)
-          @klass.find_by_id(id)
+          collection.find_by_id(id)
         end
 
         def find_by_username(username)
@@ -92,13 +92,13 @@ def find_by_username(username)
               username = username.downcase
             end
 
-            result = @klass.where(attribute => username).first
+            result = collection.where(attribute => username).first
             return result if result
           end
         end
 
         def find_by_email(email)
-          @klass.where(@klass.sorcery_config.email_attribute_name => email).first
+          collection.where(@klass.sorcery_config.email_attribute_name => email).first
         end
 
         def transaction(&blk)
diff --git a/lib/sorcery/adapters/base_adapter.rb b/lib/sorcery/adapters/base_adapter.rb
index 939fc902..cd3638c7 100644
--- a/lib/sorcery/adapters/base_adapter.rb
+++ b/lib/sorcery/adapters/base_adapter.rb
@@ -18,6 +18,10 @@ def self.find(id)
         find_by_id(id)
       end
 
+      def self.collection
+        @klass.respond_to?(:scope_for_authentication) ? @klass.send(:scope_for_authentication) : @klass
+      end
+
       def increment(field)
         @model.increment(field)
       end
diff --git a/lib/sorcery/adapters/mongoid_adapter.rb b/lib/sorcery/adapters/mongoid_adapter.rb
index 438a5095..0ba1bac7 100644
--- a/lib/sorcery/adapters/mongoid_adapter.rb
+++ b/lib/sorcery/adapters/mongoid_adapter.rb
@@ -51,7 +51,7 @@ def credential_regex(credential)
 
         def find_by_credentials(credentials)
           @klass.sorcery_config.username_attribute_names.each do |attribute|
-            @user = @klass.where(attribute => credential_regex(credentials[0])).first
+            @user = collection.where(attribute => credential_regex(credentials[0])).first
             break if @user
           end
           @user
@@ -59,15 +59,15 @@ def find_by_credentials(credentials)
 
         def find_by_oauth_credentials(provider, uid)
           @user_config ||= ::Sorcery::Controller::Config.user_class.to_s.constantize.sorcery_config
-          @klass.where(@user_config.provider_attribute_name => provider, @user_config.provider_uid_attribute_name => uid).first
+          collection.where(@user_config.provider_attribute_name => provider, @user_config.provider_uid_attribute_name => uid).first
         end
 
         def find_by_activation_token(token)
-          @klass.where(@klass.sorcery_config.activation_token_attribute_name => token).first
+          collection.where(@klass.sorcery_config.activation_token_attribute_name => token).first
         end
 
         def find_by_remember_me_token(token)
-          @klass.where(@klass.sorcery_config.remember_me_token_attribute_name => token).first
+          collection.where(@klass.sorcery_config.remember_me_token_attribute_name => token).first
         end
 
         def transaction(&blk)
@@ -75,27 +75,27 @@ def transaction(&blk)
         end
 
         def find_by_id(id)
-          @klass.find(id)
+          collection.find(id)
         rescue ::Mongoid::Errors::DocumentNotFound
           nil
         end
 
         def find_by_username(username)
           query = @klass.sorcery_config.username_attribute_names.map { |name| { name => username } }
-          @klass.any_of(*query).first
+          collection.any_of(*query).first
         end
 
         def find_by_token(token_attr_name, token)
-          @klass.where(token_attr_name => token).first
+          collection.where(token_attr_name => token).first
         end
 
         def find_by_email(email)
-          @klass.where(@klass.sorcery_config.email_attribute_name => email).first
+          collection.where(@klass.sorcery_config.email_attribute_name => email).first
         end
 
         def get_current_users
           config = @klass.sorcery_config
-          @klass.where(
+          collection.where(
             config.last_activity_at_attribute_name.ne => nil
           ).where(
             "this.#{config.last_logout_at_attribute_name} == null || this.#{config.last_activity_at_attribute_name} > this.#{config.last_logout_at_attribute_name}"
diff --git a/spec/shared_examples/user_shared_examples.rb b/spec/shared_examples/user_shared_examples.rb
index c1e09620..f40ab006 100644
--- a/spec/shared_examples/user_shared_examples.rb
+++ b/spec/shared_examples/user_shared_examples.rb
@@ -154,6 +154,20 @@
         end
       end
 
+      context 'and class implements scope_for_authentication' do
+        it 'finds user with additional conditions' do
+          allow(User).to receive(:scope_for_authentication) { User.where('1 = 1') }
+
+          expect(User.authenticate(user.email, 'secret')).to eq user
+        end
+
+        it 'does not find user with impossible conditions' do
+          allow(User).to receive(:scope_for_authentication) { User.where('1 <> 1') }
+
+          expect(User.authenticate(user.email, 'secret')).to be_nil
+        end
+      end
+
       context 'in block mode' do
         it 'yields the user if credentials are good' do
           User.authenticate(user.email, 'secret') do |user2, failure|