Walamma raa almu'minoona al-ahzaba qaloo hatha ma waAAadana Allahu warasooluhu wasadaqa Allahu (surah Ahzab: 22)

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(33:22) As for the true believers, *36 when they saw the invading confederates, they cried out: 'This is what Allah and His Messenger had promised us, and what Allah and His Messenger said was absolutely true.' *37 This only increased their faith and submission.  *38

Wa lammaa ra al mu`minoonal Ahzaaba qaaloo haaza maa wa`adanal laahu wa Rasooluh; wa maa zaadahum illaaa eemaananw wa tasleemaa

*36) After drawing attention to the model of the Holy Prophet, Allah now presents the model of his Companions so that the character of the false claimants to faith and of the sincere followers of the Messenger is clearly contrasted. Although both were alike apparently in the affirmation of the faith, both were counted as Muslims, and both attended at the Prayers, they were separated from each other as soon as the time of the trial approached, and it became clear who were loyal to Allah and His Messenger and who were Muslims only in name.
*37) Here, one should keep verse 12 in view. There it was said that when the hypocrites and the people with diseased hearts found themselves surrounded by a huge force of ten to twelve thousand men from the front and by the Bani Quraizah from behind, they openly started saying: "The promises that Allah and His Messenger had made with us were nothing but a delusion. We were promised that if we believed in Allah's religion, His succour would be at our back and we would rule Arabia and the world outside and all the wealth of Caesar and Chosroes will be ours, but here we are that the whole of Arabia is bent upon exterminating us, and there is no sign yet of the armies of the angels in sight, who would save us and protect us against this grave calamity." Now they are being told: "One meaning of the promise of Allah and His Messenger was that which was understood by these false claimants to faith. The other meaning is that which is understood by the sincere and true Muslims. When they saw the storms of danger gathering, they too remembered the promises of Allah, but these promises did not mean that as soon as they affirmed the faith they would overwhelm and subdue the whole world without the slightest effort, and the angels would come to perform their coronation, but the promises actually meant that they would have to pass through severe trials, endure extreme hardships and afflictions, offer supreme sacrifices; then only will AIlah bless them with His grace and they will be granted successes of the world and the Hereafter, which Allah has promised His believing servants.
"Do you think that you will enter Paradise without undergoing such trials as were experienced by the believers before you? They met with adversity and afflictions and were so shaken by trials that the Prophet of the time and his followers cried out: `When will Allah's help come?" - "Yes, Allah's help is near." (AI-Baqarah: 214). "Do the people think that they will be left alone after they have once said, `We have believed', and they will not be tested ? The fact is that We have put to the test all those who have gone before them. Surely, Allah has to see who are the truthful and who the liars. " (AI-`Ankabut: 2-3).
*38) That is, "On seeing the hard, times of affliction approaching they did not waver in their faith but were strengthened in it all the mote, and instead of giving uP Allah's obedience they became ready to resign and surrender to Him whatever they had with complete conviction and satisfaction of the heart. "
Here, one should fully understand that faith and resignation is indeed a quality of the self which is put to trial and test at every command and demand of the Faith. At every step in life man comes across situations where the Faith either enjoins something or forbids something, or requires one to make sacrifices of life and wealth and time and desires of the self. At every such occasion the faith and conviction of the person who deviates from obedience will suffer decline and the faith and conviction of him who submits to the command and demand will be strengthened and enhanced. Although in the beginning a man becomes a believer and Muslim only by embracing the fundamental creed (Kalimah) of Islam, yet his state of faith does not remain static but is open to both deterioration and development. Decline in sincerity and the spirit of obedience causes it to deteriorate; so much so that constant retrogression may cause the person to reach the last limits of the faith where the slightest move backward may turn him from a believer to a hypocrite. Contrary to this, the more sincere a person is, the more perfect his obedience and the greater his devotion and dedication to the cause of the true Faith, the stronger and more sound will he grow in faith and may even attain the supreme rank of the truthful. But this increase and decrease in the faith has only the moral significance which can be judged and reckoned by none but Allah. As for the man, faith is simply the act of affirmation by which a Muslim enters Islam and is regarded as a Muslim as long as he remains steadfast to it. In this regard we cannot say that so and so is half a Muslim, or one-third a Muslim, and another one double a Muslim or triple a Muslim. Likewise, in legal rights the Muslims are equal and alike. It cannot be that one is regarded a greater believer and given more rights and another one a lesser believer and given less rights. In these aspects there can be no question of the increase and decrease in the faith, and in fact, in this very sense has Imam Abu Hanifah said: "Faith in Islam neither increases nor decreases. "