Spend of that with which We have provided for you (Surah Al-Baqarah 2: 254)

Allah commands His servants to spend for His sake, in the path of righteousness, from what He has granted them, so that they acquire and keep the reward of this righteous deed with their Lord and King. Let them rush to perform this deed in this life,

before a Day comes meaning, the Day of Resurrection,

when there will be no bargaining, nor friendship, nor intercession. This Ayah indicates that on that Day, no one will be able to bargain on behalf of himself or ransom himself with any amount, even if it was the earth's fill of gold; nor will his friendship or relation to anyone benefit him. Similarly, Allah said,

Then, when the Trumpet is blown, there will be no kinship among them that Day, nor will they ask of one another [Surah Al-Mu'minun 23].

Nor intercession  meaning, they will not benefit by the intercession of anyone. Allah's statement,

and it is the disbelievers who are the wrongdoers indicates that no injustice is worse than meeting Allah on that Day while a disbeliever. Ibn Abi Hatim recorded that `Ata' bin Dinar said, "All thanks are due to Allah Who said,

and it is the disbelievers who are the wrongdoers  but did not say, `And it is the wrongdoers who are the disbelievers.'''

Source: Tafsir ibn Kathir (Abridged)