al-Qalshaanee: 

as-Salaf as-Saalih (the pious predecessors) are the first generation (and the other two who came after) who were well grounded in knowledge. Those who followed the guidance of the Prophet, safeguarding his Sunnah. 

Allaah selected them to become companions of His Prophet, and chose them to aid this religion, they struggled for the sake of Allaah in its truest sense and never tired in advising the Muslim Ummah, sacrificing themselves in order to please Allaah. 

And Allaah praised them in His book:  

مُّحَمَّدٌ رَّسُولُ اللَّهِ وَالَّذِينَ مَعَهُ أَشِدَّاء عَلَى الْكُفَّارِ رُحَمَاء بَيْنَهُمْ 

Muhammad is the Messenger of Allaah, and those who are with him (his companions) are firm against the non believers (yet) merciful amongst each other. [al-Fat-h v. 29] 

And His statement: 

 لِلْفُقَرَاء الْمُهَاجِرِينَ الَّذِينَ أُخْرِجُوا مِن دِيارِهِمْ وَأَمْوَالِهِمْ يَبْتَغُونَ فَضْلًا مِّنَ اللَّهِ وَرِضْوَانًا وَيَنصُرُونَ اللَّهَ وَرَسُولَهُ أُوْلَئِكَ هُمُ الصَّادِقُونَ  

For the poor emigrants who were expelled from their homes and their properties, seeking bounty from Allaah and [His] approval and supporting Allaah and His Messenger, [there is also a share]. Those are the truthful. [al-Hashr v. 8] 

And Allaah mentioned the Muhajireen and the Ansaar in those verses (and the following ones) praising those who came after them and showing that His pleasure lies in following their footsteps.  Similarly He warned against a severe punishment against those who go against their way (the way of the companions) Allaah said: 

وَمَن يُشَاقِقِ الرَّسُولَ مِن بَعْدِ مَا تَبَيَّنَ لَهُ الْهُدَى وَيَتَّبِعْ غَيْرَ سَبِيلِ الْمُؤْمِنِينَ نُوَلِّهِ مَا تَوَلَّى وَنُصْلِهِ جَهَنَّمَ وَسَاءتْ مَصِيرًا

And whoever opposes the Messenger after guidance has become clear to him, and follows other than the way of the believers – We will make him responsible for his choice and drive him into Hell, and evil it is as a destination.  [an-Nisaa v. 115] 

So it is upon us to follow them with regards to what they taught us about the religion. And we practise Islaam the way they practised it whilst making du’aa for them as Allaah commanded us: 

وَالَّذِينَ جَاؤُوا مِن بَعْدِهِمْ يَقُولُونَ رَبَّنَا اغْفِرْ لَنَا وَلِإِخْوَانِنَا الَّذِينَ سَبَقُونَا بِالْإِيمَانِ وَلَا تَجْعَلْ فِي قُلُوبِنَا غِلًّا لِّلَّذِينَ آمَنُوا رَبَّنَا إِنَّكَ رَؤُوفٌ رَّحِيمٌ  

As for those who came after them, they say, O our Lord forgive us our sins and (the sins of) our brothers who preceded us in faith, and do not place in our hearts any resentment towards those who have believed, our Lord, verily You are Kind and Merciful. [al-Hashr v. 10] 

  

[an-Nubad al-Waafiyyah p. 11]