Hallel means to celebrate through singing songs of praise.
The name derives from the Hebrew "Praise Thou." The singing of songs of praise was a special duty of the tribe Levi. They were to sing praises to the Lord at the time of the morning and evening offerings in the Temple. They were chosen to be the Temple personnel. God chose them because they stood with Moses against the people who worshiped the golden calf (see Exodus 32:25-29; Deuteronomy 10:6-9).
God has chosen this servant to be His Psalmist--one who carries on the ministry of praise and worship to the Lord and for the people.
My late mother, Carol J. (Roland) Wilson, demonstrated how to sing for the Lord. My late uncle and former pastor, Dewitt Roland, Sr., taught me the importance of using the Word of God to minister songs unto the Lord. He once said, "Songwriters do not have to make up words for their songs, because there are plenty in the book of Psalms."
This has allowed me to be true to the Word of God in singing songs of praise and worship.