The true God has seen fit to make known to people the outcome of the choices they decide to make. For example, God told Adam that if he ate from one tree he would die, if he did not eat from it he would not die. God told the nation of Israel, if they strictly obeyed his commands then they would remain his people with whom he had a convenant, if they did not then they would lose that special privilege. God sent his son to the earth and his son told us as it is recorded in the scriptures at John 17:3 that in order to have everlasting life we need to take in knowledge of Jesus and His father. If we don't take in knowledge of them and act on that knowledge, then we won't have everlasting life.
Having taken in knowledge of God and Jesus properly, one of the things a person finds is a commandment at Matt 28:19,20, which outlines a work for christians, true followers of Jesus, to be engaged in. And Matt 24:14 shows that this work would continue for a witness to all the nations and then the end would come.
So, we know that Jesus wants us to be involved in a preaching and teaching work because that is what he commanded his followers while on earth. We also know that if we decide to act on this knowledge we have of this command given, we can have everlasting life. What should be our ultimate motivation for doing this work that was commanded? Can we actually "earn" the reward of everlasting life through our works? To briefly paraphrase the 1980 Watchtower dated May 1st, an article entitled "Why Do What Is Right?" published by Jehovah's Witnesses, it mentioned that Jehovah's Witnesses believe that people do NOT "earn" salvation by doing works. Everlasting life is a "gift" as Romans 6:23 says. Nor do JWs believe that good works somehow wipe away sins. They do believe, however, that faith in Jesus' ransom sacrifice and an obedient inclination along with the mercy expressed by Jesus and his Father is what leads to forgiveness of sins. In effort to be obedient, and out of love for them and appreciation for what they have done for us, we should strive to do the work Jesus commanded at Matt 28:19,20. The hope of everlasting life in paradise is obviously a welcomed, much anticipated hope for us to look forward to. It was a hope, no doubt made known to us, not to be the ultimate reason for obedience, but to be an added strenthening agent and incentive.
In effort to demonstrate our faith, we should do the works commanded. James 2:14 says, "Of what benefit is it, my brothers, if a certain one says he has faith but he does not have works? That faith cannot save him, can it?" Verses- 24-26 continues to show that it is necessary to have works to demonstrate our faith.
Certainly, there is the chance that certain ones could be performing works simply seeking the reward they are expecting, feeling entitled to the reward, as if they had earned it, or doing the works seeking glory for themselves. Yet, there are also many others who are looking forward to the reward, although the reward is not the main reason they do their works. They recognize that they should be obedient to the Most High God and his son, and they know that their obedience will in turn bring glory to the Most High God. Like Jesus, they do works out of love for their heavenly father, they have a desire to do what is right to please him, they have a desire to help people to benefit themselves.
God has given us the info we need to make the decisions that will benefit ourselves. He has told us the good and the bad consequences. As far as what our individual motivations are, he knows them. We as humans cannot see someone doing a work and read his heart in order to definitely say, "He is dong this work for the wrong reason, therefore, that work is invalid." Who can accurately read hearts and minds besides the true God and Jesus? Only they are really in the best position to judge motivations.
Therefore, it doesn't seem advantageous for one to conclude that we should not do christian works, simply because we are aware of the reward that God has made available to us as a gift, and people might be doing the works only to receive a reward and glory for themselves. We need to do the works Jesus commanded, the bible makes that clear. Faith without works is dead. And we should leave it to those qualified to judge what motivations are proper and which are not.
***It was asked, if a person was not a sinner would they still need to do works? Well when Adam and Eve were created, they were created perfect and were without sin. They were given a work to do: "Be fruitful and become many and fill the earth...have in subjection...every living creature (Gen 1:28)...Gen 2:15, "And Jehovah God proceeded to take the man and settle him in the garden of Eden to cultivate it and tot ake care of it." So, they had work to do, yet it was not a work to be done in order to redeem themselves in some way. They were to be obedient because the Creator, their superior and father, gave them work to do. And out of love for their father and out of appreciation for all they were given they would have been happy to comply with the work. Jesus as well, when he came to the earth, was given a work to do and he did it even though he was without sin (John 17:4).