Rebuked them for their unbelief and hardness of heart

“But later, as the Eleven were at table, he appeared to them and rebuked them for their unbelief and hardness of heart because they had not believed those who saw him after he had been raised. He said to them, “Go into the whole world and proclaim the Gospel to every creature.” (MK 16: 14-15) 

Our Lord “rebuked them for their unbelief and hardness of heart,” and, at the same moment, He sent them to “the whole world” to “proclaim the Gospel to every creature.” He sent them not because they were perfect, but because “the whole world” needs to hear the Gospel.  

“This is the day the LORD has made; let us be glad and rejoice in it.” (Gospel Acclamation)