We should know that just like all other traditions from our Imams (a.s.), the ‘Tauqees’ issued by Hazrat Mahdi (a.t.f.s.) too contain different matters related to beliefs, origin of creation, resurrection, ethics, jurisprudence, history, science and queries about claimants, deputyship, etc. Therefore, though they have been issued in special, they are useful for all the Shias.
About the fact that we cannot fix any name and attribute for Allah :
“Allah is far above what one can describe or attribute and I purify Him (attribute inviolability to Him) by praising Him.” 
Or about Allah’s Grace:
“And Allah shows the path of guidance and rectitude and makes easy your prosperity by His Mercy.” 
Or concerning the fact that eternity of truth and destruction of falsehood is Allah’s way and custom:
“Allah has safeguarded truth along with its seekers and has set it firm in its place.” 
About the necessity of having ‘Ma’refat’ (gnosis) of Imam:
“If our Shias (may Allah grant them success in their obedience) were unanimous in carrying out their promise that lies on their shoulders, our auspicious meeting with them would not have been delayed.” 
About the fact that Imam’s existence is the source of peoples’ protection:
“We are witness and observe your supplications. May Allah protect you by that medium which Allah has bestowed upon you via His favorites (immaculate ones)” 
About the certainty of ‘Zuhoor’ (manifestation):
“Allah would complete His light even though the polytheists may dislike it” .
About Imam’s aid and assistance to his Shias:
“Anyhow, we have news about you and are aware of your condition and nothing is hidden from us about yourselves. We are aware of the wretched and helpless state that you have fallen into; from the time majority amongst you have pursued some unworthy deeds (that were abstained by your virtuous predecessors) and have broken the divine promise and pact in such manner that as if you are unaware about the existence of such pact” .
About repentance and forgiveness:
“You have erred by refusing our favours and if your seek forgiveness from Allah, surely Allah will forgive you.” 
About fulfilling the peoples’ needs:
“Inform him: ‘Lower yourself before the people (i.e., all the people should have access to you). Your place of sitting should be a corridor and you should fulfill the people’s needs. Besides, we shall assist you.” 
About the deputies:
“And Muhammad-ibn-Uthman Amri, may Allah be pleased with him as well as his father before him. He is trustworthy and reliable to me and his writings are of the same value as my writings.” 
About the third deputy:
“We are acquainted with him (May Allah bestow him with goodness and happiness and make him fortunate). We are informed of his letter and we are confident in it. He enjoys good status and position before us which has become a source of his happiness. May Allah increase His bounty for him as he is an able guardian. And all praise is for Allah, without any partner and salutations be upon His Prophet, Hazrat Muhammad and his progeny!” 
About the fourth deputy:
“O Ali-ibn-Muhammad Samori, may Allah give rewards to your brothers in the matter of your death! You will depart from this world within six days. So arrange and complete your affairs and do not make any will to appoint anyone as your successor because, ‘the major Ghaibat’ (concealment) shall commence and ‘Zuhoor’ (Reappearance) wouldn’t occur except if the Almighty Allah gives permission and that would be after long years of darkness when hearts will turn into stones and the land filled with injustice and cruelty.” 
Thus we see that a great portion of the invaluable religious heritage of our affectionate Imam (a.t.f.s.) has appeared in the form of letters and treatise.