[Heber J. Grant]
I note from your letter of the 20th, that your husband is working for the S.E.R.A. and is earning $12.00 a week; that there are five in your family and you are expecting a new arrival soon. You ask if tithing should be paid on your husband's income.
The question of tithing is one between the individual and the Lord and you must do what you think the Lord would have you do. The law of tithing is given in the Doctrine & Covenants, and I refer you particularly to Section 119 in this connection. ...
[Heber J. Grant, Letter to Zola Zena, as quoted in Minutes of the Apostles of The Church of Jesus Christ of Latter-day Saints, 1910-1951, Privately Published, Salt Lake City, Utah 2010]