Allah the Exalted orders His faithful servants to be Allah's supporters at all times, in all their statements and actions, sacrificing their selves and wealth. Allah orders them to accept His and His Messenger's call, just as the disciples said to Prophet `Isa when he said,
مَنْ أَنصَارِى إِلَى اللَّهِ
(Who are my helpers (in the cause) of Allah) meaning, `who will support me in conveying the Message of Allah, the Exalted and Most Honored'
قَالَ الْحَوَرِيُّونَ
(The Hawariyyun said:) in reference to the followers of `Isa, peace be upon him,
نَحْنُ أَنصَـرُ اللَّهِ
(We are Allah's helpers) meaning, `we will support you with regards to the Message you have been sent with and will help you convey it.' Whereby, `Isa sent the disciples to the various areas of Ash-Sham to call the Greeks and the Israelites to Islam. Similarly, during the days of Hajj, Allah's Messenger ﷺ used to ask,
«مَنْ رَجُلٌ يُؤْوِينِي حَتْى أُبَلِّغَ رِسَالَةَ رَبِّي؟ فَإِنَّ قُرَيْشًا قَدْ مَنَعُونِي أَنْ أُبَلِّغَ رِسَالَةَ رَبِّي»
(Who will support me in conveying the Message of my Lord Verily, the Quraysh have prevented me from conveying the Message of my Lord.) Allah the Exalted and Most Honored raised Al-Aws and Al-Khazraj to support the Prophet. They were the residents of Al-Madinah who gave the pledge to him and supported him, vowing to protect him from mankind and the Jinns if he migrated to them. When he migrated to them with his Companions, they fulfilled their vow to Allah. This is the reason why Allah and His Messenger called them, Al-Ansar, the Supporters. The name became synonymous with them. May Allah be pleased with them and please them, as well.
Allah said,
فَـَامَنَت طَّآئِفَةٌ مِّن بَنِى إِسْرَءِيلَ وَكَفَرَت طَّآئِفَةٌ
(Then a group of the Children of Israel believed and a group disbelieved.) When `Isa, peace be on him, conveyed the Message of his Lord to his people and the disciples supported him, a group from the Children of Israel believed. They accepted the guidance that `Isa brought to them, while another group, was led astray. This group rejected what `Isa brought them, denied his prophethood and invented terrible lies about him and his mother. They are the Jews, may Allah curse them until the Day of Judgement. Another group exaggerated over `Isa, until they elevated him to more than the level of prophethood that Allah gave him. They divided into sects and factions, some saying that `Isa was the son of Allah, while others said that he was one in a trinity, and this is why they invoke the father, the son and the holy ghost! Some of them said that `Isa was Allah, as we mentioned in the Tafsir of Surat An-Nisa'.
Allah said,
فَأَيَّدْنَا الَّذِينَ ءَامَنُواْ عَلَى عَدُوِّهِمْ
(So, We gave power to those who believed against their enemies,) vthat is, `We gave them victory over the group of Christians which defied them,'
فَأَصْبَحُواْ ظَـهِرِينَ
(and they became the victorious (uppermost).) `over the disbelieving group, when We sent Muhammad ﷺ.' Imam Abu Ja`far bin Jarir At-Tabari reported that Ibn `Abbas said, "When Allah decided to raise `Isa to heaven, `Isa went to his companions while drops of water were dripping from his head. At that time, there were twelve men at the house. `Isa said to them, `Some of you will disbelieve in me twelve times after having believed in me.' He then asked, `Who among you volunteers that he be made to resemble me and be killed instead of me; he will be with me in my place (in Paradise).' One of the youngest men present volunteered, but `Isa commanded him to sit down. `Isa repeated his statement and the young man again stood up and volunteered, and `Isa again told him to sit down. `Isa repeated the same statement and the young man volunteered. This time, `Isa said, `Then it will be you.' The appearance of `Isa was cast upon that young man, while `Isa, peace be on him, was raised to heaven through an opening in the roof of the house. The Jews came looking for `Isa and arrested the one that appeared as him, killing him by crucifixion. Some of them disbelieved in `Isa twelve times, after they had believed in him. They divided into three groups. One group, Al-Ya`qubiyyah (the Jacobites), said, `Allah remained with us as much as He willed and then ascended to heaven.' Another group, An-Nasturiyyah (the Nestorians), said, `Allah's son remained with us as much as Allah willed and He then rasied him up to heaven.' A third group said, `Allah's servant and Messenger remained with us as much as Allah willed and then Allah raised him up to Him.' The last group was the Muslim group. The two disbelieving groups collaborated against the Muslim group and annihilated it. Islam remained unjustly concealed until Allah sent Muhammad ﷺ,
فَـَامَنَت طَّآئِفَةٌ مِّن بَنِى إِسْرَءِيلَ وَكَفَرَت طَّآئِفَةٌ
(Then a group of the Children of Israel believed and a group disbelieved.) This Ayah refers to the group among the Children of Israel that disbelieved and the group that believed, during the time of `Isa,
فَأَيَّدْنَا الَّذِينَ ءَامَنُواْ عَلَى عَدُوِّهِمْ فَأَصْبَحُواْ ظَـهِرِينَ
(So, We gave power to those who believed against their enemies, and they became the victorious (uppermost).) through the victory that Muhammad ﷺ gained over the religion of the disbelievers, which brought the dominance of their religion." This is the wording in his book for the Tafsir of this honorable Ayah. Similarly, An-Nasa'i collected this statement of Ibn `Abbas in his Sunan. Therefore, the Ummah of Muhammad ﷺ will always be prevalent on the truth until Allah's command (the Final Hour) commences, while they are on this path. The last group of them will fight against Ad-Dajjal along with `Isa, peace be on him, according to Hadiths in the authentic collections. This is the end of the Tafsir of Surat As-Saff. All praise and thanks are due to Allah.