John 16:20 - Matthew Poole's English Annotations on the Holy Bible

Our Saviour's reply is no literal answer to their question, or exposition of the term which appeared so difficult to them to understand; but yet it is a substantial answer, by which he lets them know, that he should be absent from them for some time, which time would be to them a time of mourning and sadness, as he had before told them; that when the Bridegroom should be taken from them, then they should mourn; that that time would be to the wicked part of the world a time of mirth and jollity: but their sorrow should be turned into joy when they should see him again, both upon his resurrection, and in the general resurrection. The time of this life is the worldling's hour, and for the most part the power of darkness to such as love and fear God; but as the worldling's joy shall at last be turned into sorrow, (they compass themselves about with sparks, but they shall at last lie down in sorrow, Isaiah 50:11), so the godly man's sorrow shall be turned into joy: Christ will say to the good servant, Enter thou into the joy of thy Lord, Matthew 25:23.