Revelation 21:4-5, "And God shall wipe away all tears from their eyes; and there shall be no more death, neither sorrow, nor crying, neither shall there be any more pain: for the former things are passed away. (5) And he that sat upon the throne said, Behold, I make all things new. And he said unto me, Write: for these words are true and faithful."
I believe this passage teaches that there will be no tears in heaven because there will no longer be death, sorrow, or pain. The former things are passed away. There are no tears in heaven.
Revelation 5:4, "And I wept much, because no man was found worthy to open and to read the book, neither to look thereon".
John wept much when no one could be found worthy to open the seven seal scroll. While it is true that this is the only place in the Scriptures where someone is mentioned as crying in heaven, we must remember that John was not in heaven in a glorified body and not in the New Jerusalem [eternal state].
Revelation 4:2, "And immediately I was in the spirit: and, behold, a throne was set in heaven, and one sat on the throne." John's feet were on the Isle of Patmos while his vision was in heaven.
There is a mention of the martyred tribulation saints having no tears in heaven even though they probably cried much in the tribulation before their martyrdom.
Revelation 7:17, "For the Lamb which is in the midst of the throne shall feed them, and shall lead them unto living fountains of waters: and God shall wipe away all tears from their eyes."
There is also a mention of Israel not having tears in the Millennial Kingdom.
Isaiah 25:8, "He will swallow up death in victory; and the Lord GOD will wipe away tears from off all faces; and the rebuke of his people shall he take away from off all the earth: for the LORD hath spoken it."
John MacArthur says, "God will swallow up death, which itself functions as a swallower of human beings (Isa. 5:14; Pro. 1:12). Paul notes the fulfillment of this promise in the resurrection of believers (1 Cor. 15:54). The Lord God will remove the sorrow associated with death (cf. Isa. 65:19). Revelation alludes to the tender action of this verse twice-once in Isa. 7:17 to describe the bliss of the redeemed in heaven, and once in Isa. 21:4 to describe ideal conditions in the New Jerusalem."