Christian author and theologian John Piper has suggested that a famous quote by Nelson Mandela regarding racism, which when posted by former U.S. President Barack Obama became the most popular tweet of all time, might not hold up to the teaching of Scripture.

Piper said in an article posted on Desiring God on Friday that he has several thoughts about Mandela’s quote, which Obama tweeted in August in response to a white nationalist rally held in Charlottesville, Virginia, where one woman was killed after a driver plowed his car into a crowd. The former president’s tweet reportedly garnered over 4.6 million likes.

Mandela’s quote comes from his 1994 autobiography Long Walk to Freedom, where he wrote: “No one is born hating another person because of the color of his skin, or his background, or his religion. People must learn to hate, and if they can learn to hate, they can be taught to love, for love comes more naturally to the human heart than its opposite.”

Piper broke down the quote and said it’s “tricky” when it comes to how it holds up with the Bible.

The theologian pointed out that the Bible teaches that humans have a nature that is rebellious against God and are unwilling and unable to submit to God’s law and to please God.

He said that humankind’s fallen nature and sinfulness that is resistant to God is largely shaped by parents and culture.

“One form this sinfulness can take is hatred toward people who are different from us. This attitude can become bigoted and angry, wanting to create as much separation as we can. But another form our selfishness can take is a way of relating that wins the praise of others by doing helpful things for others — even others who are different from us,” Piper wrote.

“There are many vain, selfish, anti-God people who have learned to treat others with decency and respect because there are very significant advantages to living that way, especially if there’s a group of people that you care about — a group of people who praise that behavior very highly, and thus build up your ego while you treat people that way,” he added.

When it comes to the part of the quote that people “can be taught to love,” Piper argued that the Bible has a different way of explaining love.

“Paul says in 1 Corinthians 13:3, ‘If I give away all I have, and if I deliver up my body to be burned, but have not love, I gain nothing.’ So the love that the Bible cares about is not merely giving our goods to the poor or being willing to sacrifice our bodies. Love, as 2 Corinthians 8:1–2 describes, starts with being overwhelmed by being loved by God and being overwhelmed by the grace of God to us in our guilt and our lack of deserving,” Piper said.

“Then, overflowing with joy in God, we meet the needs of others and draw them into sharing our joy in God, which doesn’t just last for 80 years but for 80,000 years. This love goes out to people unlike us — in fact, especially to people not like us. Jesus says we give love to our enemies. We pour out that kind of love.”

The author explained that it is not really loving to teach people to act lovingly if it is without the love of God.

When it comes to the part where the former South African president said that “love comes more naturally to the human heart than its opposite,” Piper argued that that is true if love “simply means doing many beneficial things for people.”

He positioned, however, that “apart from Christ and His saving work, that natural love exists in a heart that is hostile to God, a heart that does not submit to his law.”

“Every one of us has a fundamentally self-exalting heart, which, to be sure, will do many things that benefit others. But that heart has no expression of submission to God or desire that others find their joy in God,” he continued.

The Reformed theologian said, “if love, as the Bible teaches, is far more than learned behaviors — if it is the overflow of joy in being forgiven through Jesus Christ and finding Him as our supreme treasure and desiring that others come and join us in that everlasting pleasure, even at great cost to ourselves — then love does not come naturally to the human heart.”

“It is, in fact, diametrically opposed to what we are by nature,” he added.

Christian leaders and believers have meanwhile been strongly speaking out against racism in America. Thousands of Christians took a knee in prayer on the National Mall on Columbus Day earlier this week, asking God to forgive the racial sins of the country’s past and let reconciliation and healing sweep the land.