The emphasis is Hendriksen's. Knight, The Pastoral Epistles , 88. Knight, The Pastoral Epistles , 81. However, it is somewhat common for Paul to not use an article after doing so previously in the context. The function of the article carries over from verse 8 to verse 9 which means that Paul is referring to the same law in both verses.
Several commentators agree.
18 Knight, The Pastoral Epistles , 84. There are two words which refer to the fifth commandment. It is very clear from the words themselves that each points to the fifth commandment. The list follows the order of the Ten Commandments. The first three pairs cover offenses against God, while the vices mentioned are all violations of the second table of the law.