No man can serve two masters: for either he will hate the one, and love the other; or else he will hold to the one, and despise the other. You cannot serve God and mammon.
All Commentaries on Matthew 6:24 Go To Matthew 6
Augustine of Hippo
“He will be devoted to one and disregard the other.” He does not say that one will hate the other, for scarcely anyone’s conscience could hate God. But one disregards God— that is to say, one does not fear God but presumes on his goodness. From this negligent and tormented confidence, the Holy Spirit recalls us when he says through the prophet: “Son, do not add sin to sin; and do not say, ‘The mercy of God is great.’ ” Note when Paul says, “Do you not know that God’s kindness is meant to lead you to repentance?” For whose mercy can be accounted as great as the mercy of him who forgives all, if they convert to him? He makes the wild olive a partaker of the fatness of the original olive tree. At the same time, whose severity can be accounted as great as the severity of him who has not spared the natural branches but has broken them off because of unbelief? Therefore, whoever wishes to love God and to beware of offending him, let such a one cleanse the upright intention of his heart from all duplicity. In this way, he will “think of the Lord in goodness and seek him in simplicity of heart.” .