Page 421 of the standard 604-page Madani mushaf falls in juz 21 and contains 8 verses from Surah Al-Ahzab. The page break matches the printed mushaf, so you can follow along with a physical copy or track a memorisation plan page by page.
Among the faithful are men who fulfill what they have pledged to Allah: there are some among them who have fulfilled their pledge, and some of them who still wait, and they have not changed in the least,
33:24
that Allah may reward the true for their truthfulness, and punish the hypocrites, if He wishes, or accept their repentance. Indeed Allah is all-forgiving, all-merciful.
33:25
Allah sent back the faithless in their rage, without their attaining any advantage, and Allah spared the faithful of fighting, and Allah is all-strong, all-mighty.
33:26
And He dragged down from their strongholds those who had backed them from among the People of the Book, and He cast terror into their hearts, [so that] you killed a part of them, and took captive [another] part.
33:27
He bequeathed you their land, their houses and their possessions, and a territory you had not trodden, and Allah has power over all things.
33:28
O Prophet! Say to your wives, ‘If you desire the life of the world and its glitter, come, I will provide for you and release you in a graceful manner.
33:29
But if you desire Allah and His Apostle and the abode of the Hereafter, then Allah has indeed prepared a great reward for the virtuous among you.’
33:30
O wives of the Prophet! Whoever of you commits a gross indecency, her punishment shall be doubled, and that is easy for Allah.