It is well-known that Chazal said “A man must always complete the chapters of the Torah together with the congregation twice reading the words and once with the Targum (Aramaic translation), as anyone who does this will have his days and years lengthened!”. The ideal time to perform this is on Friday, but those people who are preoccupied with their livelihoods during the week should do it on the morning of Shabbos. The Kabbalists write that when reading these portions of the Torah one should be extremely careful to read it with all of the correct stresses and tunes. About such a commandment which has reward at its side and long life on its right, one who does not bother to fulfil it will surely be punished. This can be in two ways. If he does not believe in the words of Chazal who promised that one who is stringent about this will merit long life, he will be punished for his lack of belief. If, on the other hand, he does believe and nevertheless does not bother fulfilling it and is not worried about his life, he has sinned with his soul and will be punished like someone who deliberately commits suicide. This is especially true as this is something which is extremely easy to fulfil, and when one commences fulfilling it for the wrong reasons one will end up fulfilling it for the right reasons, which are to give pleasure to our Father in heaven for the portions of the Torah are the holy sayings of Hashem, and they have heavenly secrets in every letter, and the entire Torah is made up of Names of Hashem, and even when the reader is does not think about all of these secrets they work by themselves and the work of our hands works for us.
The simple explanation why Chazal added the reading of the Targum was so that we could understand what we are saying, as in those days they only understood Aramaic, in which case nowadays he best way would be to learn it together with the explanation of Rashi. However, according to the mystical part of the Torah even nowadays one should read the Targum. A righteous man therefore will hold his path and do both of them. One who does not waste his time will be able to do both on the same Shabbos day.
