Mr. Bush published a video message on Saturday urging unity amid the coronavirus’ outbreak, which received 4 million views on Twitter as of Sunday morning.

“.@PeteHegseth “Oh bye the way, I appreciate the message from former President Bush, but where was he during Impeachment calling for putting partisanship aside. @foxandfriends He was nowhere to be found in speaking up against the greatest Hoax in American history!” Mr. Trump tweeted.

Mr. Bush’s message called for people to ignore partisanship to better protect the most vulnerable to the coronavirus and to assist those who have become unemployed.

“[L]et us remember how small our differences are in the face of this shared threat,” Mr. Bush said. “In the final analysis we are not partisan combatants, we are human beings equally vulnerable and equally wonderful in the sight of God. We rise or fall together, and we are determined to rise.”