Cawthorn’s personal style of evangelism — which appears to be a talking-to-strangers model many Christians, like me, literally never contemplate — doesn’t seem terribly winsome. But evangelism is not a strange thing for Christians. The final command Jesus gave in the Gospel of Matthew was for his followers to expand their ranks, and from the Christian perspective, trying to convert people is grounded in love. If you accept foundational Christian beliefs about God and humanity, declining to share your faith isn’t respectful but negligent, apathetic, and cruel.
The message of undivided allegiance Warnock gave is equally ordinary for Christians. “You can’t serve God and the military,” he said, as Rubio quoted. Then he continued: “You can’t serve God and money. You cannot serve God and mammon at the same time. America, choose ye this day whom you will serve.”
With this full context, it’s obvious — as I’m sure Rubio, a Catholic, knows perfectly well — Warnock is quoting from Jesus’s best-known teaching, the Sermon on the Mount, and a famous Old Testament story. It is a common practice of Christian instruction to replace “money,” the original alternative Jesus gave to serving God, with anything that could compete for loyalty and love we owe to God alone. The point is not to prohibit things like the military or money (to make that case you’d need other biblical support) but to insist that God gets ultimate priority in the Christian life, no matter the cost.