1.In the Quran 3:159 “…then when you have taken a decision, tawakkal (put your trust )in Allah. Syed Qutb , says that the Rasul s.a.w. quotes this verse when the sahabah went to see him and ask whether he would want to reconsider the decision to protect Medina at Uhud . The lesson to be drawn is that once a decision has been taken, one should not entertain thoughts of reconsidering, etc. but rather act it out resolutely. In this case he will still uphold the decision to protect Medina at Uhud .

a)Is the tradition relating to the quotation of the verse during this incident a sahih one?
b)Could you inform me of other verses that stressed on the firmness & resoluteness of character and to avoid being indecisive?
2.One of the important teachings of Islam is to be truthful. It is no doubt relevant when dealing with people/society.
However does it apply equally in the realm of our psychology & subsconscious mind? In Psychology,it is a well known fact that one can change oneself through positive self-affirmation & visualisation .It is believed that the self-affirmations to the subconscious mind is best done in an “already achieved mode”. For example,a student who is weak in mathematics and wish to improve on it should say the self-affirmations as “I am excellent at mathematics” & also visualize himself as ALREADY being good at Maths repeatedly(even though he is not that good at the moment). Or a person who is a coward could reprogram his mind by saying to himself,” I am brave”,etc. This is so that the subconscious mind is set with the positive intended goal and thus will program the whole body with the message.
But the question is that such self-affirmation is not the truth (or not the truth yet).
When he is telling himself that he is ALREADY being good at Maths, he is actually “lying “ to himself. But is it acceptable in Islam in this case?
In surah al-Anfaal verse 43 & 44 describes how Allah makes the Muslims see the enemy as small in number whereas they are actually LARGER than the Muslims. So it seems it is allowable to “lie” to oneself in a positive way?
Also the concept of “husnul zann” of giving “70 excuses” when dealing with Muslims show that we prefer to see the positive aspects rather than the real truth?

It is never wise to deceive onself, or God, as it confuses our perspective, and God never was confused at all. On your assertions about the power of postive thinking in paragraph 2, I challenge you to find any evidence for them.

Now on "lying". Why would anyone lie to themselves, or to try to lie to God? Think on that. After you finally argue that it is for the better good (common rationale for telling "white lies"), then ask what is the difference between a deception, a white lie, and a damn lie. Answer: No difference.
That ought to answer your question.
Now, a thought on selfimprovement. It is far better to list weaknesses and strengths, work on the weaknesses, and monitor their improvement with concrete objective data. Using positive thoughts of "I can improve" only works if you have a plan for improvement.
On seeing "husnul zann" we often prefer to avoid seeing and thinking about truth. If someone, even a Muslim, is a dirty stinking dog, thinking otherwise seldom changes them. If you child is a liar, ignoring it is not likely to change their behavior. Yes, it is convienent often to ignore truth, for religious or other reasons.
Good luck with your studies. Know thyself.

1a) Determining whether a tradition is sahih (authentic) or not involves a process of evaluating its chain of narration (isnad) and the reliability of each narrator. Since I am an AI and cannot access specific hadith sources or evaluate them individually, I'm unable to confirm the authenticity of the tradition you mentioned. It is best to refer to reputable scholars or reliable hadith collections to determine the authenticity of specific traditions.

1b) There are several verses in the Quran that emphasize the importance of firmness and resoluteness of character. Here are a few examples:

- Surah Al-Hajj (22:78): "And strive for Allah with the striving due to Him. He has chosen you and has not placed upon you in the religion any difficulty. [It is] the religion of your father, Abraham. Allah named you "Muslims" before [in former scriptures] and in this [revelation] that the Messenger may be a witness over you and you may be witnesses over the people. So establish prayer and give zakah and hold fast to Allah. He is your protector; and excellent is the protector, and excellent is the helper."

- Surah Al-Mumtahanah (60:8): "Allah does not forbid you from those who do not fight you because of religion and do not expel you from your homes - from being righteous toward them and acting justly toward them. Indeed, Allah loves those who act justly."

- Surah Al-Fussilat (41:30): "Indeed, those who have said, "Our Lord is Allah " and then remained on a right course - the angels will descend upon them, [saying], "Do not fear and do not grieve but receive good tidings of Paradise, which you were promised."

These verses, among others, emphasize the importance of remaining steadfast in one's faith, upholding justice, and staying committed to the path of righteousness.

2) In Islam, honesty and truthfulness are highly valued, both in our interactions with others and within ourselves. However, when it comes to self-improvement and personal development, the concept of positive thinking and self-affirmation can be approached differently.

While it is important to have positive thoughts and aspirations, it is also crucial to acknowledge and work on one's weaknesses and limitations honestly. Islam encourages self-reflection, self-criticism, and self-improvement through sincere efforts and by seeking guidance from Allah.

The example you mentioned from Surah Al-Anfal (8:43-44) refers to a specific situation during a battle where Allah provided reassurance and increased the believers' confidence. This does not necessarily promote lying to oneself but rather highlights the concept of relying on Allah's support and strengthening one's resolve when faced with challenges.

Regarding the concept of "husnul zann" (thinking positively or giving others the benefit of the doubt), it is encouraged within the context of dealing with fellow Muslims and assuming the best about their intentions. However, this does not mean disregarding the truth, but rather maintaining a positive outlook and avoiding hasty assumptions or negative judgments.

Ultimately, Islam promotes truthfulness and honesty, but it also acknowledges the importance of positive thinking, seeking Allah's help, and striving to improve oneself while remaining grounded in reality.