Every finite-dimensional Lie algebra of characteristic 
has a faithful
finite-dimensional representation.
Iwasawa's Theorem
See also
Ado's Theorem, Lie AlgebraExplore with Wolfram|Alpha
References
Jacobson, N. Lie Algebras. New York: Dover, pp. 204-205, 1979.Referenced on Wolfram|Alpha
Iwasawa's TheoremCite this as:
Weisstein, Eric W. "Iwasawa's Theorem." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/IwasawasTheorem.html