I’ve been reminded repeatedly of this truth recently:
Who are you to pass judgment on the servant of another? It is before his own master that he stands or falls. And he will be upheld, for the Lord is able to make him stand. Romans 14:4 English Standard Version (ESV)
The immediate context is the weaker brother among those in the church at Rome, which was composed of former Jews trained to obey the Law and regulations and others who were never exposed to those regulations. Each looked down on the other for their freedoms and bondages.
Nowadays we look down on a brother (or sister) if they don’t dress the way we do, or perform ceremonies the way we do, work for an employer the way we do, or look at the world the way we do, or behave as responsibly as we do. I could go on. I’m sure you could supply more examples.
About this scripture passage, John Calvin comments:
To his own Lord he stands or falls, etc. As though he said, — “It belongs rightly to the Lord, either to disapprove, or to accept what his servant doeth: hence he robs the Lord, who attempts to take to himself this authority.” And he adds, he shall indeed stand: and by so saying, he not only bids us to abstain from condemning, but also exhorts us to mercy and kindness, so as ever to hope well of him, in whom we perceive anything of God; inasmuch as the Lord has given us a hope, that he will fully confirm, and lead to perfection, those in whom he has begun the work of grace [emphasis mine].
Lately, I’ve tried to practice what Calvin says constitutes true worship:
“God is not worshipped by external ceremonies, but when men forgive and bear with one another, and are not above measure rigid.”
and
“God values faith and kindness much more than sacrifices and all ceremonies.”
We would do well to follow his advice.