diff --git a/lib/alexa_ruby/request/base_request/validator.rb b/lib/alexa_ruby/request/base_request/validator.rb
index b2a10c9..00d1243 100644
--- a/lib/alexa_ruby/request/base_request/validator.rb
+++ b/lib/alexa_ruby/request/base_request/validator.rb
@@ -25,7 +25,11 @@ def initialize(cert_chain_url, signature, request, timestamp_diff = nil)
     #
     # @return [Boolean]
     def valid_request?
-      raise ArgumentError, 'Outdated request' unless timestamp_tolerant?
+      unless timestamp_tolerant?
+        raise ArgumentError,
+              'Outdated request: request timestamp is more than ' \
+              "#{@timestamp_diff} seconds later than current time"
+      end
       valid_uri? && valid_certificates?
     end
 
diff --git a/lib/alexa_ruby/request/base_request/validator/certificates.rb b/lib/alexa_ruby/request/base_request/validator/certificates.rb
index 12bcb9a..b5a6a90 100644
--- a/lib/alexa_ruby/request/base_request/validator/certificates.rb
+++ b/lib/alexa_ruby/request/base_request/validator/certificates.rb
@@ -20,10 +20,7 @@ def initialize(certificates_chain_url, signature, request)
     #
     # @return [Boolean]
     def valid?
-      raise ArgumentError, 'Inactive Amazon SSL certificate' unless active?
-      raise ArgumentError, 'Inactive host in SSL certificate' unless amazon?
-      raise ArgumentError, 'Signature and request mismatch' unless verified?
-      true
+      active? && amazon? && verified?
     end
 
     private
@@ -42,14 +39,24 @@ def download_certificates(certificates_chain_url)
     # @return [Boolean]
     def active?
       now = Time.now
-      @cert.not_before < now && @cert.not_after > now
+      (@cert.not_before < now && @cert.not_after > now) ||
+        raise(
+          ArgumentError,
+          'Amazon SSL certificate is outdated ' \
+          "specified dates: #{@cert.not_before} - #{@cert.not_after}"
+        )
     end
 
     # Check if Subject Alternative Names includes Amazon domain name
     #
     # @return [Boolean]
     def amazon?
-      @cert.subject.to_a.flatten.include? 'echo-api.amazon.com'
+      @cert.subject.to_a.flatten.include?('echo-api.amazon.com') ||
+        raise(
+          ArgumentError,
+          'Certificate must be issued for "echo-api.amazon.com" ' \
+          "(given certificate subject: #{@cert.subject.to_a})"
+        )
     end
 
     # Check if given signature matches given request
@@ -58,7 +65,12 @@ def amazon?
     def verified?
       sign = decode_signature
       pkey = public_key
-      pkey.verify(hash, sign, @request)
+      pkey.verify(hash, sign, @request) ||
+        raise(
+          ArgumentError,
+          'Given request signature does not match with request SHA1 hash ' \
+          "(signature: #{sign})"
+        )
     end
 
     # Decode base64-encoded signature
diff --git a/lib/alexa_ruby/request/base_request/validator/uri.rb b/lib/alexa_ruby/request/base_request/validator/uri.rb
index b6a4a8d..2d75640 100644
--- a/lib/alexa_ruby/request/base_request/validator/uri.rb
+++ b/lib/alexa_ruby/request/base_request/validator/uri.rb
@@ -14,11 +14,7 @@ def initialize(uri)
     #
     # @return [Boolean]
     def valid?
-      raise ArgumentError, 'Certificates chain URL must be HTTPS' unless https?
-      raise ArgumentError, 'Not Amazon host in certificates URL' unless amazon?
-      raise ArgumentError, 'Invalid certificates chain URL' unless echo_api?
-      raise ArgumentError, 'Certificates chain URL must be HTTPS' unless port?
-      true
+      https? && amazon? && echo_api? && port?
     end
 
     private
@@ -27,28 +23,48 @@ def valid?
     #
     # @return [Boolean]
     def https?
-      @uri.scheme == 'https'
+      @uri.scheme == 'https' ||
+        raise(
+          ArgumentError,
+          'Certificates chain URL must be an HTTPS-enabled endpoint ' \
+          "(current endpoint: #{@uri})"
+        )
     end
 
     # Check if URI host is a valid Amazon host
     #
     # @return [Boolean]
     def amazon?
-      @uri.host.casecmp('s3.amazonaws.com').zero?
+      @uri.host.casecmp('s3.amazonaws.com').zero? ||
+        raise(
+          ArgumentError,
+          'Certificates chain host must be equal to "s3.amazonaws.com" ' \
+          "(current host: #{@uri.host})"
+        )
     end
 
     # Check if URI path starts with /echo.api/
     #
     # @return [Boolean]
     def echo_api?
-      @uri.path[0..9] == '/echo.api/'
+      @uri.path[0..9] == '/echo.api/' ||
+        raise(
+          ArgumentError,
+          'Certificates chain URL path must start with "/echo.api/" ' \
+          "(current path: #{@uri.path})"
+        )
     end
 
     # Check if URI port is 443 if port is present
     #
     # @return [Boolean]
     def port?
-      @uri.port.nil? || @uri.port == 443
+      @uri.port.nil? || @uri.port == 443 ||
+        raise(
+          ArgumentError,
+          'If certificates chain URL has a port specified, it must be 443 ' \
+          "(current port: #{@uri.port})"
+        )
     end
   end
 end