Charles H. Spurgeon on Psalms 71:21

Thou shalt increase my greatness. As a king, David grew in influence and power. God did great things for him, and by him, and this is all the greatness believers want. May we have faith in God, such as these words evince. And comfort me on every side. As we were surrounded with afflictions, so shall we be environed with consolations. From above, and from all around, light shall come to dispel our former gloom; the change shall be great, indeed, when the Lord returns to comfort us. Here is the final vow of praise.