Note 8 at 1 Cor. 16:20: It was a middle Eastern custom to greet one another with a kiss, as it still is today. However, Paul is not just restating a custom that was already practiced. That would be unnecessary. He was at the least saying that Christians should express their brotherly love towards each other. Many people in Western cultures would be offended by a kiss. Discretion should be used. It has to be a holy kiss, implying that there is an unholy kiss. If it offends the person receiving it, it's not proper.