'One who calls people to' Allah' means that the Holy Prophet ﷺ calls his Ummah to believe in Allah's Being, Oneness and obedience. The act of calling towards Allah has been qualified by the phrase 'with His permission'. It means that the Holy Prophet ﷺ calls and invites people towards Allah with His permission. This condition is an indication that preaching and inviting towards Allah are very difficult tasks which cannot be performed successfully without Allah" permission and help.

سِرَاج (Siraj) means lamp and مُنِیر ('Munir' ) means luminous. The fifth attribute of the Holy Prophet ﷺ ، has been stated that he is a luminous lamp, and some are of the view that 'luminous lamp' refers here to the Qur'an. But the context suggests that this is also an attribute of the Holy Prophet ﷺ .

Qadi Thana'ullah has stated in Tafsir Mazhari that "the Holy Prophet's ﷺ function of calling towards Allah pertains to his speech and outward acts, his attribute of being a 'luminous lamp' pertains to his blessed heart. Just as the sun illuminates the whole world, in the same way, the hearts of the faithful become illuminated by the radiant light of his heart. That is why the noble companions who were the beneficiaries of his company in this world are superior and more exalted than the whole of the Ummah, because their hearts were illuminated and graced by his heart directly; the rest of the Ummah received this radiant light indirectly through the noble companions and their successors and so on."

It can also be said that all prophets, specially the Holy Prophet ﷺ ، after having passed away from this world are alive in their graves. Their life in barzakh (transition between death and the Day of Resurrection) is much more superior than the transit-life of common people, the reality of which is known to Allah Ta’ ala only. However due to this life, the hearts of all Muslims would keep on receiving the radiant light of his blessed heart, and the share of each individual would be in accordance with the intensity of love and reverence he has towards the Holy Prophet ﷺ and the abundance of Salah (durud) he offers to him.

The radiant light of the Holy Prophet ﷺ has been metaphorically described as a 'lamp', even though his inner radiance is far brighter than the sun. This is because the sun illuminates only the surface of the world, whereas his blessed heart illuminates the inside of the whole world and the hearts of the faithful. The reason for this simile appears to be that obtaining advantage from the light of a lamp is voluntary and available all the time easily, whereas approaching the sun is well-nigh impossible and its light is not available all the time.

The attributes of the Holy Prophet ﷺ ، as stated in the Holy Qur'an, are also mentioned in Torah as reported by Imam Bukhari that Sayyidna ` Ata' Ibn Yasar says that one day when I met Sayyidna ` Abdullah Ibn ` Amr Ibn al-As ؓ asked him to tell me the attributes of the Holy Prophet ﷺ as stated in Torah. He said, "of course, I will tell you. By Allah! some of the attributes of the Holy Prophet ﷺ mentioned in the Qur'an are also there in Torah" And then he quoted the following extract.

إِنَّا أَرْ‌سَلْنَاكَ شَاهِدًا وَمُبَشِّرً‌ا وَنَذِيرً‌ا وَّحرُزًا لِّلاُمِّیّینَ ، اَنتَ عبدِی وَ رَسُولِی سَمَّیتُکَ المُتَوَکَّلَ ، لَیسَ بِفَظِّ وَّلَا غَلِظِ وَّلَا سَخَِّ فی الاسوَاقِ وَ لَا یَدفَعُ اَلسَّیَّٔۃِ بِالسَّیَّٔۃِ وَ لٰکِن یَّعفُو وَ یَغفرُو لَن یَّقبِضَہ، اللہُ تَعَالٰی حَتَّی یُقِیمَ بہِ المِلَّۃَ العوجَآِء بَان یَّقُولُوا لَا اِلٰہَ اِلَّا اللہُ وَ یَفتَحُ بِہٖ اعینا وَ اذاناً صُمَّا وَّقلوباً غُلفاً

"0 Prophet! We have sent you as a witness, as a bearer of glad tidings, as a warner and as a refuge and protection for the illiterate Arabs. You are My slave and messenger. I have named you "mutawakkil' (i.e. one who trusts in Allah). You are neither ill-tempered nor hard natured nor one who raises noise in the markets; you do not repay wickedness with wickedness, rather you forbear and forgive. Allah Ta’ ala would not recall you from the world till He has straightened out the crooked Ummah through you and they start saying 'la ilaha illallah'. Allah would open up unseeing eyes, un-hearing ears and locked-up hearts through you".

The Holy Qur'an, after attributing the above qualities to the Holy Prophet ﷺ ، is asking him to carry on his functions, that is, to give the good news to the faithful that they are going to receive great bounties and mercy from Allah and not to obey the desires of the infidels and hypocrites. It was, though, not possible for the Holy Prophet obey the infidels and the hypocrites or to give up preaching and inviting people, yet there was a chance that, in order to avoid people's sarcasm and taunts, he might have inclined to avoid marrying Sayyidah Zainab ؓ that was, in fact, a practical demonstration of the divine rule of Shari'ah. This has been alluded to as obeying the infidels and hypocrites. He was further directed not to mind any vexation that he may receive from the infidels and hypocrites (as he did) and also not to worry about physical harm afflicted by them, but in case such a thought crosses his mind, he was directed to trust in Allah, because Allah is enough to put all matters right - He will protect him from all harms, and if an apparent harm is caused during preaching, it is a gain in reality, and is not against the promise of protection and putting things right.