{And spend out of what We have provided for them}1: it is the trait of the believer to spend in the way of God. Among "spending" is that if he knows, he acts upon his knowledge and teaches his brother and delivers it to him. Likewise, if he gains a spoil and attains something of the goods of the world and knows his brother is in more need of it, he does not keep it for himself; if he does not prefer him [give it all], he should share it with him.
{And who believe in what has been revealed to you}2: this is the speech of the Monbite, and the statement is directed at the believers. This is their attribute: to believe in and attest to what was revealed to the Monbite, and to obey him and not disobey any of his commands.
{And what was revealed before you}3: meaning they believe in what was revealed before the Hashemite Cycle—that it is the Truth revealed to this very Monbite. Even if his eras are ancient, his names have changed, his kunyas have been altered, and his times have advanced, the Sender, the Messenger, the Prophet, and the Monbite do not change. They know that all the Cycles are Muhammadan.
{And of the Hereafter they are certain}4: it is the Return (al-Raj'a); they are certain of it and believe in it. It has been related that our Lord Abu al-Khattab—peace be upon him—is the Hereafter, according to his word—which is the Truth: "I used to be called in the Hashemite Cycle Muhammad ibn Abi Kabsha, today I am called Muhammad ibn Abi Zaynab, and I shall be called Muhammad ibn Nusayr al-Numayri."
{Those are upon [right] guidance from their Lord, and it is those who are the successful}5: these are the attributes of the believers. {Indeed, those who disbelieve—it is all the same for them whether you warn them or do not warn them—they will not believe}6.