Joseph Smith Translation, Genesis 14

37 And he lifted up his voice, and he blessed Abram, being the high priest, and the keeper of the storehouse of God.
38 Him whom God had appointed to receive tithes for the poor.
39 Wherefore, Abram paid unto him tithes of all that he had, of all the riches which he possessed, which God had given him more than that which he had need.

(Emphasis added)

On the evening of the 29th of November, I united in prayer with Brother Oliver for the continuance of blessings. After giving thanks for the relief which the Lord had lately sent us by opening the hearts of the brethren from the east, to loan us $430; after commencing and rejoicing before the Lord on this occasion, we agreed to enter into the following covenant with the Lord, viz.:

That if the Lord will prosper us in our business and open the way before us that we may obtain means to pay our debts; that we be not troubled nor brought into disrepute before the world, nor His people; after that, of all that He shall give unto us, we will give a tenth to be bestowed upon the poor in His Church, or as He shall command; and that we will be faithful over that which He has entrusted to our care, that we may obtain much; and that our children after us shall remember to observe this sacred and holy covenant; and that our children, and our children's children, may know of the same, we have subscribed our names with our own hands.

(Signed)

Joseph Smith, Jun.
Oliver Cowdery.

https://byustudies.byu.edu/hc/2/13.html#HOC
(emphasis added)