"But because I have said these things to you, sorrow has filled your heart."
Jesus, John 16:6
Jesus said these words to His disciples after telling them He was leaving them. He also told them what they would have to suffer because of knowing Him. They would be kicked out of the synagogue, they would be hated, and some would be killed. Because He said these things, sorrow had filled their heart.
He mentions that none of them had asked where He was going (vs 5). They were thinking more about what would happen to them and how His departure would affect them, rather than taking on a heavenly perspective of what was happening. They didn't stop to ask, what was God doing?
While Jesus was with them, they were safe. Yet, He says it was to their advantage (and ours) that He left (vs 7). Because of His death and resurrection, all who believe in Him may receive the Holy Spirit. The benefit of this is that many believers can spread throughout the world, preaching the gospel of the kingdom with signs following.
Jesus living here as one man could only do so much, but with many filled with His Spirit, the fruit of His life multiplies. This is fundamental to how the kingdom works--a seed is sown and much fruit results.
Are you sorrowful? Try looking at your situation from a heavenly perspective. Ask the Lord "where He is going" or where is He leading you right now, rather than focusing on the difficulty you are experiencing.
Replace the sorrow in your heart with the joy of what His resurrection accomplished. Ask Him about your place in preaching the gospel of the kingdom. Then get ready, because those filled with His Spirit will do the works that He did, and greater works because He left the earth to go to the Father (John 14:12). This is not a time to allow our hearts to be filled with sorrow, but a time to stand up, brush ourselves off, and get to work!