D. Martyn Lloyd-Jones
“Christianity or Religion” a sermon on John 4:28-39
https://www.mljtrust.org/sermons/book-of-john/christianity-or-religion/
In many ways religion may be our greatest danger. We can worship religion, and we can be very religious without God. I mean by that, that we can be very punctilious in the observance of days and times and seasons. We can fast, we can deny ourselves things, and the whole time we are just centering upon ourselves and thinking about how we are going to improve ourselves and make ourselves better. We are trying to get certain lessons for ourselves, and the whole thing may be really self-centered. We may be highly religious, but there may be not place for God; and even if he does come in, he is simply there as someone who may be of help to us. We are at the center of our religion; our religion really is a religion without God.
“Gain To Me”, a sermon on Philippians 3:7 on Paul's conversion
https://www.mljtrust.org/sermons/face-to-face-with-christ/gain-to-me/
You can be sincerely wrong. You can be genuinely mistaken. (Saul) was as (sincerely religious) as a man could be. But it isn't sincerity that matters... It's truth that matters. You see, he was sincere about the wrong thing.
The Christian message, my friend, is to say this, that every man must be born again... God must come and take your soul and fashion it afresh.
“Ungodliness” a sermon on Romans 1:18
https://www.mljtrust.org/sermons/book-of-romans/ungodliness/
You can be religious without being godly. You can enjoy public worship without knowing God. You can like the thing itself―religion, preaching, singing, praying and all these things. But there's no real knowledge of God and no real thirst for him. And there is nothing more terrible than that.
“The Living God” (God Who Acts) delivered at the Minister’s Conference June 1971 and published in The Evangelical Magazine of Wales
https://christianlibrary.org.au/index.php/sermons/275-the-living-god
Religion is generally the greatest enemy of the Christian faith. To be a religious person is one of the greatest hindrances to becoming a Christian, because it gives certain satisfactions. And we know today that, speaking of the churches in general in this land, there are congregations with an alarming percentage of people who are religious but who are not Christians. Religion is dangerous, you see, for this reason, that it is always something that puts emphasis upon our activities, our practices - we practise religion. And thereby we tend to think that it is entirely a matter of our activities, our conduct and behaviour, with the result that God is nearly always forgotten - taken for granted, of course, but therefore forgotten.