The above describes that the Prophet (صلى الله عليه و آله وسلم) taught Sahabah the Quran, trained them in wisdom and purified their Nufoos.

It is in Quran - لَقَدْ مَنَّ اللَّـهُ عَلَى الْمُؤْمِنِينَ إِذْ بَعَثَ فِيهِمْ رَسُولًا مِّنْ أَنفُسِهِمْ يَتْلُو عَلَيْهِمْ آيَاتِهِ وَيُزَكِّيهِمْ وَيُعَلِّمُهُمُ الْكِتَابَ وَالْحِكْمَةَ وَإِن كَانُوا مِن قَبْلُ لَفِي ضَلَالٍ مُّبِين [Certainly did Allah confer (a great) favor upon the believers when He sent among them an Apostle from themselves, reciting to them His verses and purifying them and teaching them the Book and wisdom, although they had been before in manifest error.] (Aal-e-Imran - 164).

The process of teaching, training and purification of Sahabah was as follows.

(i) Sahabah first accepted Islam on the hands of Prophet Mohammad (صلى الله عليه و آله وسلم). They gave promise of allegiance (Ba'it - بیعت) by reciting Islamic testimony (کلمہ طیّبہ).

It is in Quran - "إِنَّ الَّذِينَ يُبَايِعُونَكَ إِنَّمَا يُبَايِعُونَ اللَّهَ يَدُ اللَّهِ فَوْقَ أَيْدِيهِمْ ۚ فَمَن نَّكَثَ فَإِنَّمَا يَنكُثُ عَلَىٰ نَفْسِهِ ۖ وَمَنْ أَوْفَىٰ بِمَا عَاهَدَ عَلَيْهُ اللَّهَ فَسَيُؤْتِيهِ أَجْرًا عَظِيمًا" [ Indeed, those who pledge allegiance to you, (O' Prophet ﷺ) they are actually pledging allegiance to Allah. The hand of Allah is over their hands. So he who breaks his word only breaks it to the detriment of himself. And he who fulfills that which he has promised Allah, He will give him a great reward.] (Al-Fath - 10).

Sometimes, the Prophet (صلى الله عليه و آله وسلم) took promise of allegiance (بیعت) as repentance for one’s past wrong doings. Sometimes the pledge (بیعت) was taken to shed the last drop of blood in the cause of Islam, as it happened at the time of the conflict of Hudaibiya. The Promise of allegiance was also taken from women.

(ii) After people became Muslims, Prophet Mohammad (صلى الله عليه و آله وسلم) taught them Quran.

(iii) Prophet Mohammad (صلى الله عليه و آله وسلم) then trained Sahabah in their day to day living. He also taught them wisdom.

It is in Quran لَّقَدْ كَانَ لَكُمْ فِي رَسُولِ اللَّهِ أُسْوَةٌ حَسَنَةٌ لِّمَن كَانَ يَرْجُو اللَّهَ وَالْيَوْمَ الْآخِرَ وَذَكَرَ اللَّهَ كَثِيرًا [Indeed in the Apostle of Allah (صلى الله عليه و آله وسلم) you have an excellent example to follow; for him who hopes in (the meeting with) Allah and the Last Day and does Zikr of Allah extensively.] (Al-Ahzaab - 21)

(iv) When Sahabah sat in the company of Prophet Mohammad (صلى الله عليه و آله وسلم) their worldly thoughts and ordinary consideration got extincted from their minds and they became exceptionally pious. This aspect is referred in the above Quranic verse as 'purification' ('وَيُزَكِّيهِمْ').

It is in Hadith - Hanzalah Al-Usayyidi (رضئ الله تعالى عنه) said, "O'Apostle of Allah (صلى الله عليه و آله وسلم), when we are in your company, and are reminded of Hell-fire and Jannah, we feel as if we are seeing them with our own eyes, but when we go away from you and attend to our wives, children and business, much of these things go out of our minds." Thereupon the Apostle of Allah (صلى الله عليه و آله وسلم) said, "By Him in Whose Hand is my life, if your state of mind remains the same as it is in my presence and you are always busy in the Zikr of Allah, the angels will shake hands with you in your beds and on roads. (Muslim - part of the Hadith).

After Prophet Mohammad (صلى الله عليه و آله وسلم) left this world, the teaching, training and purification of the people was carried out by Khulafa-e-Rashideen, Sahabah, Aimma and Shuyookh of Ihsan and Awliya Allah.

The above verse describes that the teaching, training and purification started by Prophet Mohammad (صلى الله عليه و آله وسلم) is still continued by his blessings by the chosen people of his Ummah and it is applicable for all people of the world till the day of resurrection.