In The Name of Allaah, The Most Merciful, The Bestower of Mercy
The Messengers are the most judicious amongst the creation without exception, and after them their followers are the most judicious group. The people of the scriptures and the great legislated laws are the most judicious amongst the followers of the Messengers and the Muslims are the most judicious amongst them [i.e. amongst all those who received divine scriptures and great legislated laws].
The companions of Muhammad [peace and blessings be upon him] are the most judicious amongst the Muslims and then those who followed them exactly in faith. The people who adhere steadfastly to the authentic tradition of the Prophet and the authentic narrations transmitted from him are the most judicious amongst the Muslim nation without exception after companions and those who adhered to their path.
The clear evidence showing that the Messengers are the most judicious amongst the entire creation is that the beneficial knowledge they have brought- the righteous actions and the beneficial affairs related to true wellbeing in this worldly life and the afterlife- has not emerged from others or something even close it. There is nothing- from any perspective- that emerged from other judicious people that can be compared to what the Messengers brought with regards to beneficial knowledge, righteous action and the beneficial affairs of true wellbeing in this worldly life and the afterlife.
Whoever ponders upon their personal life stories – in specific and in general, their patience and perseverance, their abstinence from those unnecessary lawful pleasures of the worldly life, their fervent desire for Allaah’s pleasure and the reward Allaah has kept in the afterlife, their purified manners, the fact that they are the most truthful amongst the creation, (possessors) of the most righteous hearts and the most purified souls, trustees of the greatest trust (i.e. revelation and Messenger ship), the noblest of those whom a person can accompany, the purest in their innermost conscience, the purest with regards to their private affairs- will not doubt the fact that they are the most judicious amongst Allaah’s creation without exception. There is no doubt that whoever is closer to them [i.e. follows them properly], then his (or her) share of judiciousness will be more than (that of others). [Ref 1]
Comprehensive Guidance of The Messenger
Muhammad’s [sallal-laahu-alayhi-wasallam] Ummah is not in need of anyone after him; rather the only need they have is someone to convey what he came with. Muhammad’s [sallal-laahu-alayhi-wasallam] message is comprehensive, universal and preserved. This universality, comprehensiveness and preservation is not limited to [any time and place], rather it is comprehensive for those to whom Muhammad [sallal-laahu-alayhi-wasallam] was sent [i.e. the whole world] and likewise with regards to everything that is needed in the fundamental and subsidiary issues of the religion.
Muhammad’s [sallal-laahu-alayhi-wasallam] message is sufficient, all embracing and universal- nothing else is needed besides it. It has not isolated any affair of truth needed by his Ummah in their sciences and deeds. The Messenger of Allaah [sallal-laahu-alayhi-wasallam] did not leave this world until he acquainted his Ummah with everything. He even taught them the etiquettes of using the toilet; the etiquettes of sexual relations; the etiquettes of sleep and after waking up; the etiquettes of eating, drinking and travel.
He acquainted them with the etiquettes of speech and silence; the etiquettes of keeping company with the people and seclusion. He acquainted them with the affairs of illness, good health, poverty and wealth. He acquainted them with all the affairs of life and death. He described Allaah’s throne, the angels, the jinn, the hell fire and the day of judgement in such a manner as if one has seen them with the naked eye. He [sallal-laahu-alayhi-wasallam] informed them about their Lord and His Perfect Names and Attributes, and that Allaah alone is their true object of worship.
He acquainted them with the Prophets of old and their nations – the events that took place between them and their nations – in such a manner as if one was present at that time. He acquainted them with all the means to good and the paths of evil- in general and in detail- which no other prophet informed his nation. He acquainted them with death and what will take place in the grave – either bliss or punishment. He acquainted them with the evidences and proofs of Tawheed [i.e. the oneness of Allaah in His Lordship, Names and Attributes, and that Allaah alone has the right to be worshipped].
He acquainted them with Prophet hood and the affairs of the Afterlife, and he refuted all the sects of disbelief and misguidance. He acquainted them with war strategies- how to confront the enemy, the way to achieve victory and conquests. If only they knew and understood these affairs in the correct manner [i.e. the manner it should be understood], they would not be overcome by their enemy. He acquainted them with the plots of Iblees and the ways through which he approaches them, and the ways to repel those plots and plans. He acquainted them with the soul- its characteristics and faults- in such a manner that they are not in need of anyone else to tell them about it. He taught them how to live their daily lives and had they acknowledged and acted upon this, then their worldly affairs would be firmly established. He brought them all the means of success in this life and the next, and they do not need anyone besides him. So how can it be said that the path of Muhammad [sallal-laahu-alayhi-wasallam] is in need of something else outside of it. The reason for such a claim is due to the weak and little understanding of a person. Allaah [The Most High] said:
أَوَلَمْ يَكْفِهِمْ أَنَّا أَنزَلْنَا عَلَيْكَ الْكِتَابَ يُتْلَىٰ عَلَيْهِمْ ۚ إِنَّ فِي ذَٰلِكَ لَرَحْمَةً وَذِكْرَىٰ لِقَوْمٍ يُؤْمِنُونَ
Is it not sufficient for them that We have sent down to you the Book (the Qur’an) which is recited to them? Verily, herein is mercy and a reminder (or an admonition) for a people who believe. [29:51]
Allaah [The Most High] said:
وَنَزَّلْنَا عَلَيْكَ الْكِتَابَ تِبْيَانًا لِّكُلِّ شَيْءٍ وَهُدًى وَرَحْمَةً وَبُشْرَىٰ لِلْمُسْلِمِينَ
And We have sent down to you the Book (the Qur’an) as an exposition of everything, a guidance, a mercy, and glad tidings for those who have submitted themselves (to Allah as Muslims). [16:89]
Allaah [The Most High] said:
يَا أَيُّهَا النَّاسُ قَدْ جَاءَتْكُم مَّوْعِظَةٌ مِّن رَّبِّكُمْ وَشِفَاءٌ لِّمَا فِي الصُّدُورِ وَهُدًى وَرَحْمَةٌ لِّلْمُؤْمِنِينَ
O mankind! There has come to you a good advice from your Lord [i.e. the Qur’an, ordering all that is good and forbidding all that is evil], and a healing for that [disease of ignorance, doubt, hypocrisy and differences, etc.] in your breasts, – a guidance and a mercy [explaining lawful and unlawful things, etc.] for the believers. [10:57]
[Ref 1: An Excerpt from As-Sawaa’iq Al-Mursalah 4/1514. slightly paraphrased]
[Ref 2: An Excerpt from I’laam Al-Muwaqqi’een 4/375-377- slightly paraphrased]