“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. Ye cannot serve God and mammon.”
Matthew 6:24 — Greek Interlinear
Church Fathers on Matthew 6:24
The Lord had said above, that he that has a spiritual mind is able to keep his body free from sin; and that he who has not, is not able. Of this He here gives the reason, saying, 'No man can serve two masters.'
Otherwise; it had been declared above, that good things become evil, when done with a worldly purpose. It might therefore have been said by some one, I will do good works from worldly and heavenly motives at once. Against this the Lord says, 'No man can serve two masters.'
Or otherwise; in what had gone before He had restrained the tyranny of avarice by many and weighty motives, but He now adds yet more. Riches do not only harm us in that they arm robbers against us, and that they cloud our understanding, but they moreover turn us away from God’s service.