The entire pasuk reads, “And He pays to the person whom He hates, to his face [in order] to destroy him, He will not delay [to reward] the one whom He hates, to his face He will pay him.” (Divarim: 7; 10)
From the above pasuk, we learn that the person who is among those whom HaShem hates receives his entire reward in this world in order to ensure that he does not receive any portion in The World to Come. (RaSh”I) Therefore, the individual who is evil to the extent that he is one of those whom HaShem hates, though he may commit evil, his reward would still come to him, as he is reward in this world.
According to the Torah T’mimah, the reward of the evildoer (i.e. those whom HaShem hates) is dispensed without delay, in this world. However, those who are completely righteous, their reward will be experienced in The World to Come. (In the first chapter of maseches Peah (also quoted after the blessing recited before Torah study, there is a list of ten mitzvos for which a person who performs them is guaranteed to benefit in this world and nevertheless retain the principle of the reward for The World to Come. In terms of the other mitzvos, the individuals who are completely righteous would have to wait to begin attaining their reward in The World to Come.)
The Ohr HaChaim on the pasuk points out that the first mention of the one whom HaShem hates is written in the plural – לשנאיו (l’son’av), while the second mention is written in the singular - לשונא (l’son’oh). This teaches us that there is a major difference between the individual who would have descendants who are similarly hated by HaShem and those evildoers who have descendants who are not hated by HaShem. Those who will have descendants who are evildoers and are hated by HaShem, similar to them, will be completely rewarded in this world in order that they will not live in The World to Come. However, if such evildoers will have descendants who are not hated by HaShem, these individuals will not be compensated in this world, at least to the degree that they will lose their portion in The World to Come. This follows that which is taught in maseches Sanhedrin (104a), that a son brings merit to a father. Therefore, though the father may have been one of those hated by HaShem, the mitzvos performed by the son can bring merit to the father after the father has passed away.
According to one of the meforshim (possibly the MaLBI”M), the above explanation that the evildoers whom HaShem hates receive their entire reward in this world and thereby do not have any merit remaining to receive their reward in The World to Come, is true prior to the time of the coming of Mashiach. However, subsequent to the coming of Mashiach, the one whom HaShem hates will be paid forthright through his being destroyed.