Rupertus Meldenius, a 17th century German theologian, was quoted as saying, “In essentials unity, in nonessentials liberty, in all things charity.”
There are essential things that Christians must agree on (such as the statements in the Nicene Creed, for example). There are also nonessential beliefs that can vary from one generation or tradition to another, like whether men should wear hats inside a church building or worship style of the congregation. But in all things, essential or not, we must exercise charity, the kindness that comes from a motive to love one another.
Source: https://www.ligonier.org/learn/articles/essentials-unity-non-essentials-liberty-all-things/
