Humans did not evolve from monkeys or apes. however, we do share a common ancestor.
why is this an important distinction to make note of when discussing human evolution

As monkeys and apes have a common ancestor, there will be marked resemblance between monkeys, humans and apes. These study of these resemblance will let us know which organisms are closer  and hence shall be placed closer in the phylogenetic tree.

While discussing human evolution, one will keep in mind the similarities that humans have with the apes and monkeys. Both genotype and phenotype similarities and differences can be measured among the organisms.

It will also help in the study of mutation of genes present in humans, apes and monkeys.