Exodus 25:1–27:19

תְּרוּמָה - a voluntary offering
Giving is a test of the heart.
And יהוה spake unto Moses, saying, Speak unto the children of Israel, that they bring me an offering: of every man that giveth it willingly with his heart ye shall take my offering. And this is the offering which ye shall take of them; gold, and silver,and brass, And blue, and purple, and scarlet, and fine linen, and goats' hair,And rams' skins dyed red, and badgers' skins, and acacia wood, [acacia containsa number of organic compounds that defend the wood from pests and decay] Oil for the light, spices for anointing oil, and for sweet incense, Onyx stones, and stones to be set in the ephod, and in the breastplate. And let them make me asanctuary; that I may dwell among them. According to all that I shew thee after the pattern of the tabernacle, and the pattern of all the instruments thereof, even so shall ye make it. Exodus 25:1-11

Terumah - free will offering(s). The silver is mine, and the gold is mine, saith יהוה of hosts.  Haggai 2:8
Since יהוה owns everything one can only return to him was what was already his. Gold represents a genuine giver; Silver a calculating giver;Brass a frugal.
But this I say, He which soweth sparingly shall reap also sparingly; and he which soweth bountifully shall reap also bountifully. Every man according as he purposeth in his heart, so let him give; not grudgingly, or of necessity: for God loveth a cheerful giver.II Corinthians 9:6 
Naw-than' – a requirement: 
And יהוה spake unto Moses, saying, When thou takest the sum of the children of Israel after their number, then shall they give every man a ransom for his soul unto יהוה , when thou numberest them; that there be no plague among them, when thou numberest them. This they shall give, every one that passeth among them that are numbered, half a shekel after the shekel of the sanctuary: (a shekel is twenty gerahs:) an half shekel shall be the offering of יהוה . Every one that passeth among them that are numbered, from twenty years old and above, shall give an offering unto .יהוה  Exodus 30:11-14
Acacia tree

And they shall make an ark of acacia wood: two cubits and a half shall be the length thereof, and a cubit and a half the breadth thereof, and a cubit and a half the height thereof. And thou shalt overlay it with pure gold, within and without shalt thou overlay it, and shalt make upon it a crown of gold round about. And thou shalt cast four rings of gold for it, and put them in the four corners thereof; and two rings shall be in the one side of it, and two rings in the other side of it. And thou shalt make staves of shittim wood, and overlay them with gold. And thou shalt put the staves into the rings by the sides of the ark, that the ark may be borne with them. The staves shall be in the rings of the ark: they shall not be taken from it. Exodus 25:10-15

The Ark of the Covenant (Hebrew: ארון ב ה ר ב י רית Aron Habrit), also known as the Ark of the Testimony. The Ark was made of acacia wood impervious to pests that would damage it; corruptness can not enter the heart that is right with the Father. The overlay of gold both inside and out typifies a pure heart. Gold is recognizable, desired, rare, appealing, valuable, unchanging; won't rust, decay, burn; refined by heat. Gold is extracted from the earth at great expense, effort and often hardship, and historically increases in supply at about the same rate as the growth in world population. As יהוה desired to dwell in Israel's midst , so today יהוה desires to dwell in our hearts. John_14:23 aHaishua answered and said unto him, If a man love me, he will keep my words: and my Father will love him, and we will come unto him, and make our abode with him.
Ark of the Covenant

Malachi 3:8-9 Will a man rob God? Yet ye have robbed me. But ye say, Wherein have we robbed thee? In tithes and offerings. Ye are cursed with a curse: for ye have robbed me, Malachi 3:10 Bring ye all the tithes into the storehouse, that there may be meat in mine house, and prove me now herewith, saith the LORD of hosts, if I will not open you the windows of heaven, and pour you out a blessing, that there shall not be room enough to receive it.

Print PDF