The verse describes an event that occurred several days prior to the crucifixion. Jesus entered Jerusalem, greeted by His people as the Messiah who would free them from Roman rule. The entry of Jesus on a donkey fulfills prophecy and signifies the peaceful nature of His first coming. Here, Hosanna is a Hebrew term that refers to a cry of praise or a prayer for salvation.
Despite Christ's earthly ministry lasting for three years, Israel was still in unbelief, and Jesus knew they would reject Him as their king. His heart broke when He thought of Jerusalem and Israel. Because He knew they would suffer the terrible time of Jacob's Trouble if they rejected Him. This is the time of Great Tribulation when God's wrath will be poured out until His chosen people truly recognize Him and what He has done for them.
Similarly, we will find ourselves in a similar situation. On the day of judgment, we will say with one voice, " Hosanna, Blessed is he that cometh in the name of the Lord." And then everyone will witness Him descending from heaven to establish His Millennial Kingdom, in which we will be united with Him.

Dear Heavenly Father, the truth of Your Word tells us everything from the beginning to the end. Thank You for keeping Your promises to Israel despite their centuries of unbelief. Thank You for keeping Your promises to me and to the Christian Church in Christ Jesus, my Savior, even when my faith has faltered, and my pride has caused me to lose sight of You. I pray that my life and work will be to Your praise and glory. 
In Jesus's name I pray. Amen.