gains..
For instance. boomer bought XYZ stock for $10,000.... 40 years later he still owns it and it's worth $250,000. He's never paid tithing on the increase, but feels he owes the Lord 10% of $240,000. So he instructs the executor to cut a check to the church for $24,000 and to distribute the remaining $226,000 to his/her heirs.