His, the Exalted, words: “Allah is pleased with them and they are pleased with Him.” Because they angered their pagan relatives and openly opposed them, Allah—glorified and exalted be He—rewarded them with His good pleasure. Thus, for having provoked the displeasure of their unbelieving kin, they were compensated with the pleasure of Allah. Allah is pleased with them, and they are pleased with Him.
His words: “Those are the party of Allah” mean the group that sides with Allah. As for the unbelievers, they too form a party, for Allah says about them, “Those are the party of Satan” (al-Mujādilah 19)—the followers and helpers of Satan—whereas these believers are the helpers of the Lord.
This discussion, then, concerns showing enmity toward the disbelievers and refraining from allying with them. It does not require us to boycott them in every worldly matter and mutual benefit; several exceptions apply.
First: Despite our dislike and enmity toward them, we must still invite them to Allah—glorified and exalted be He. We are not to abandon them with the remark, “These are the enemies of Allah and our enemies.” Rather, it is incumbent on us to summon them to Allah in the hope that He will guide them. If they refuse, and we possess the ability, we fight them: either they embrace Islam, or—if they are Jews, Christians, or Zoroastrians—they pay the jizya (poll-tax).