This is important because it helps to preserve the meaning of the original source material and to avoid any confusion about the timeline of events or the speaker's perspective.
Here are some examples of how to maintain the tense of a block quote:
Source material (past tense): "The president delivered his speech yesterday."
Block quote (past tense): "In his speech yesterday, the president said..."
Source material (present tense): "The company is expanding its operations."
Block quote (present tense): "The company says it is expanding its operations."
Source material (future tense): "The new product will be released next year."
Block quote (future tense): "The company announced that the new product will be released next year."