The greatest investment the righteous can make is in the support of the work of salvation and morality in society. Unlike any other money spent, it is only the support of the Gospel minister where money is directly invested into blessing our fellow human beings by the teaching of salvation and morality. This is especially serious in this day and age when evil is pervasive and has become mainstream. Here in Malachi God promise blessings for those who are honest supporter of this work of counteracting darkness.
Malachi3:8 Will a man rob God? Yet ye have robbed me. But ye say, Wherein have we robbed thee? In tithes and offerings.
3:9 Ye [are] cursed with a curse: for ye have robbed me, [even] this whole nation.
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].
3:11 And I will rebuke the devourer for your sakes, and he shall not destroy the fruits of your ground; neither shall your vine cast her fruit before the time in the field, saith the LORD of hosts.
3:12 And all nations shall call you blessed: for ye shall be a delightsome land, saith the LORD of hosts.