Its true that in the Holy Quran it has been frequently asked that we should mind the duties of Allah swt and have Taqwa which is some how defined as fear of God but actual meaning of Taqwa is have discipline in our life and follow the commands of Allah swt so we can achieve salvation and Sa'dat in this world and hereafter. Also it has said that no one can do intercession but except those whom He will give the permission.
If you read this holy verse:
Surah Al-Baqara, Verse 255:
اللَّهُ لَا إِلَٰهَ إِلَّا هُوَ الْحَيُّ الْقَيُّومُ لَا تَأْخُذُهُ سِنَةٌ وَلَا نَوْمٌ لَّهُ مَا فِي السَّمَاوَاتِ وَمَا فِي الْأَرْضِ مَن ذَا الَّذِي يَشْفَعُ عِندَهُ إِلَّا بِإِذْنِهِ يَعْلَمُ مَا بَيْنَ أَيْدِيهِمْ وَمَا خَلْفَهُمْ وَلَا يُحِيطُونَ بِشَيْءٍ مِّنْ عِلْمِهِ إِلَّا بِمَا شَاءَ وَسِعَ كُرْسِيُّهُ السَّمَاوَاتِ وَالْأَرْضَ وَلَا يَئُودُهُ حِفْظُهُمَا وَهُوَ الْعَلِيُّ الْعَظِيمُ
Allah is He besides Whom there is no god, the Everliving, the Self-subsisting by Whom all subsist; slumber does not overtake Him nor sleep; whatever is in the heavens and whatever is in the earth is His; who is he that can intercede with Him ☆☆☆(but by His permission?) ☆☆He knows what is before them and what is behind them, and they cannot comprehend anything out of His knowledge except what He pleases, His knowledge extends over the heavens and the earth, and the preservation of them both tires Him not, and He is the Most High, the Great.
مَن ذَا الَّذِي يَشْفَعُ عِندَهُ إِلَّا بِإِذْنِهِ يَعْلَمُ
☆☆☆(but by His permission?) ☆☆
But intercession doesn't mean that we do frequently mistakes or sin in our daily lives hoping just on the Day of Judgment Prophet and Aimmah (a.s) will do intercession for us. We have asked for forgiveness purely and sincerely from Allah after any mistakes done and not to repeat it again anad again. Also we should feel guilty. Then if we have done this we might have intercession on the day of Judgment inshallah.