Minn. R. Evid. 602
A witness may not testify to a matter unless evidence is introduced sufficient to support a finding that the witness has personal knowledge of the matter. Evidence to prove personal knowledge may, but need not, consist of the witness' own testimony. This rule is subject to the provisions of rule 703, relating to opinion testimony by expert witnesses.
Minn. R. Evid. 602
Committee Comment-1977
The rule states a fundamental principle of evidence law. Expert witnesses provide the only exception to the rule that witnesses must testify from firsthand knowledge. See rule 703. The rule, although phrased in terms of competency, is essentially a specific application of rule 104(b) . Testimony simply is not relevant unless the witness testifies from firsthand knowledge
The requirement of firsthand knowledge does not preclude a witness from testifying as to a hearsay statement which qualifies as an exception to the hearsay rule (see Article 8) and was heard by the witness. Whereas the witness in such circumstances could repeat the hearsay statements the witness could not testify as to the subject matter of the statements without firsthand knowledge. See United States Supreme Court Advisory Committee Note.
The rule requires that witnesses have firsthand knowledge. It does not specifically refer to the declarant of a hearsay statement that is admitted subject to an exception to the hearsay rule. With the exception of party admissions, which are admitted as a function of the adversary system (and are not hearsay under rule 801(d) (2) the Courts have generally required that the declarant of a hearsay statement have firsthand knowledge, before the hearsay statement is admissible. The rule should be read to continue this practice. See C. McCormick, Evidence sections 18, 264, 285, 300, 310 (2d ed. 1972) .