What exactly is the connection between doing one’s duty and pursuing the truth? What does doing one’s duty have to do with achieving salvation?

The Answer from God’s Word:

It is always through the process of doing his duty that man is gradually changed, and it is through this process that he demonstrates his loyalty. As such, the more you are able to do your duty, the more truths you shall receive, and so too shall your expression become more real. Those who merely go through the motions in doing their duty and do not seek the truth shall be eliminated in the end, for such men do not do their duty in the practice of truth, and do not practice truth in the fulfillment of their duty. Such men are those who remain unchanged and will be cursed. Not only are their expressions impure, but what they express is nothing but wickedness.

from “The Difference Between the Ministry of the Incarnate God and the Duty of Man” in The Word Appears in the Flesh

You should do your own duty to the best of your ability with open and upright hearts, and be willing to do whatever it takes. As you have said, when the day comes, God will not mistreat anyone who has suffered or paid a price for Him. This kind of conviction is worth holding on to, and you should never forget it. Only this way can I put My mind at ease about you. Otherwise, I will never be able to put My mind at ease regarding you, and you will forever be the objects of My distaste. If you all can follow your conscience and give your all for Me, spare no effort for My work, and devote a lifetime of effort to My gospel work, then won’t My heart often jump for joy for you? Won’t I be able to entirely put My mind at ease regarding you?

from “On Destination” in The Word Appears in the Flesh

If you are very glad to be a service-doer in the house of God, working diligently and conscientiously in obscurity, always giving and never taking, then I say that you are a loyal saint, because you seek no reward and are simply being an honest man. If you are willing to be candid, if you are willing to expend your all, if you are able to sacrifice your life for God and stand witness, if you are honest to the point where you know only to satisfy God and not to consider yourself or take for yourself, then I say that these people are those who are nourished in the light and who shall live forever in the kingdom.

from “Three Admonitions” in The Word Appears in the Flesh