Should we not ask God for help?

If you are ordinary person you should follow the rules of your deeds and nature. If you are a devotee, even then, you should not ask God for help. Your devotion must not aspire any result. You are asking God for help means that you want God to violate his own natural rules. The impression of millions of angels and sages is disturbed if God violates his own rules. That will give a poor impression on God. You are putting God to inconvenience by forcing him to use his supernatural power. Whether you are a devotee or not, you must always try to solve your problems by putting your best effort.

If you fail, even then, do not ask God to help you. Then, you think that it is your fate and worship God as usual. Arjuna was fighting with his grandfather, Bhishma. Arjuna was not putting up his best effort to kill Bhishma. He was having sympathy to Bhishma, who has brought up Arjuna. Noting this, Krishna took His Sudarshana chakra and ran to kill Bhishma. That means the Lord tried to solve the problem of Arjuna through His divine power. Arjuna did not agree to this and forced Krishna to stop, because Arjuna knew about his inadequate effort. But when Sindhava was to be killed, Arjuna tried his best, because Arjuna took an oath to kill Sindhava before sunset and otherwise he promised that he would enter the fire.

Since the sunset took place apparently due to the Maya of Krishna, Arjuna stopped fighting and wanted to enter the fire. He was just going to jump into the fire but he never asked for help. He thought that was his fate. Therefore, the Lord helped him secretly. Therefore, if you put your best effort, still fail because it is beyond your limits, if you happen to be a real devotee and do not ask for the help from God, then you will be helped by the superpower secretly. The secrecy is due to preservation of the sacredness of his administration in the eyes of others.