Joy and sorrow exist concurrently in the hearts of born again believers in the Lord Jesus Christ.
"As sorrowful, yet always rejoicing" (II Corinthians 6:10).
"Even in laughter the heart is sorrowful; and the end of that mirth is heaviness" (Proverbs 14:13).
In our present experience, gladness and grief are not mutually exclusive. We live in a world declared by Scripture to be "full of the goodness of the Lord", but that also "lieth in wickedness" (Psalm 33:5; I John 5:19). Thus, we will know both realities as we rightly perceive life in terms of the living Word of God, the Lord Jesus, and the written Word, the Bible. In our most difficult moments, the Holy Spirit works within us to administer His assurance that all is well "though the earth be removed, and though the mountains be cast into the sea" (Psalm 46:2). In times of happiness and pleasure, the same Spirit tempers our present joy so that we do not forget that this present world is not our home. Moreover, He reminds us that even as we laugh, other brothers and sisters weep. "Remember them that are in bonds, as bound with them; and them which suffer adversity, as being yourselves also in the body" (Hebrews 13:3).
The dual reality of joy and sorrow strengthens us with hope, and sobers us with realization. The believer who understands such truth cannot be overwhelmed by pain, nor deceived by pleasure. We require both delight and difficulty in our present existence as we walk with "the Man of sorrows" who is also the One "annointed with the oil of gladness above Thy fellows" (Isaiah 53:3; Hebrews 1:9). A joyful heart in sorrow. A sorrowful heart in laughter. Some cannot imagine how such things can be. Those who well know the Lord Jesus understand that presently, such things cannot be otherwise. Again, we live in a world so filled with God's goodness that "the Light shineth in darkness" (John 1:5). Nevertheless, this world is not that Home where "God shall wipe away all tears" (Revelation 21:4). We wait for that wondrous day and that glorious place, with sorrows transcended by joy, and joy tempered by sorrow.
"And now shall mine head be lifted up above mine enemies round about me: therefore will I offer in His tabernacle sacrifices of joy; I will sing, yea, I will sing praises unto the LORD."