The right attitude toward material supply
19 "Do not lay up for yourselves treasures on the earth, where moth and rust ruin and where thieves break in and steal; 20 but lay up for yourselves treasures in heaven, where neither moth nor rust ruins and where thieves neither break in nor steal; 21 because where your treasure is there your heart will be also.That is the crucial question: where is your heart? It should be obvious that the best place to have your savings account is in the Bank of Heaven. So how does one make deposits up there? You do it by investing in the Kingdom.
About worldview
22 "The lamp of the body is the eye. So if your eye is sound, your whole body will be full of light.Of course we have two eyes, but the Text has "eye" in the singular. I take it that the reference is to the way we interpret what we see (which is our real ‘eye’)—two people, one pure and one vile, observing the same scene will give very different interpretations to it. 23 But if your eye is evil, your whole body will be full of darkness."Evil" here has the idea of malignant—aggressively evil. Someone with a malignant mind will give an evil interpretation to everything he sees, and in consequence his being will be filled with unrelenting darkness. Compare Titus 1:15. So if the light that is in you is darkness, how great is that darkness!
"You cannot serve God and money"
24 "No one is able to serve two masters; for either he will hate the one and love the other, or he will be loyal to the one and despise the other. You cannot serve God and money.The Text has "mammon", which presumably includes more than just money; anyone who has materialistic values is serving mammon. But I fear that comparatively few speakers of English today know the word, so I put ‘money’.