Deuteronomy 14:29

Then Yahweh said to Aaron, “You shall have no inheritance in their land nor own any portion among them; I am your portion and your inheritance among the sons of Israel.

“Now to the sons of Levi, behold, I have given all the tithe in Israel for an inheritance, in return for their service which they perform, the service of the tent of meeting.

and houses full of all good things which you did not fill, and hewn cisterns which you did not dig, vineyards and olive trees which you did not plant, and you will eat and be satisfied,

“And you shall be glad before Yahweh your God, you and your sons and daughters, your male and female slaves, and the Levite who is within your gates, since he has no portion or inheritance with you.

“You shall generously give to him, and your heart shall not be grieved when you give to him, because for this thing Yahweh your God will bless you in all your work and in all that you send forth your hand to do.

and you shall be glad before Yahweh your God, you and your son and your daughter and your male and female slaves and the Levite who is within your gates and the sojourner and the orphan and the widow who are in your midst, in the place where Yahweh your God chooses for His name to dwell.

“When you reap your harvest in your field and have forgotten a sheaf in the field, you shall not go back to get it; it shall be for the sojourner, for the orphan, and for the widow, in order that Yahweh your God may bless you in all the work of your hands.

“When you have finished paying all the tithe of your produce in the third year, the year of tithing, then you shall give it to the Levite, to the sojourner, to the orphan, and to the widow, that they may eat within your gates and be satisfied.

“Bring the whole tithe into the storehouse, so that there may be food in My house, and test Me now in this,” says Yahweh of hosts, “if I will not open for you the windows of heaven and empty out for you a blessing until it is beyond enough.

Pure and undefiled religion before our God and Father is this: to visit orphans and widows in their affliction, and to keep oneself unstained by the world.