Here is a little excerpt from Isaac Watts biography.
Watts is credited by many with introducing hymns to the English churches when his Hymns and Spiritual Songs was first published in 1707. They are extensively used today due to his poetic gifts, but also because he interpreted the Old Testament using knowledge of the New. This set an example for later hymn writers. Isaac Watts explained his methods as follows: “Where the Psalmist describes religion by the fear of God, I have often joined faith and love to it. Where he speaks of pardon of sin through the mercies of God, I have added the merits of a Saviour. Where he talks of sacrificing goats and bullocks, I rather mention the sacrifice of Christ, the Lamb of God. When he attends the ark with shouting into Zion, I sing of the ascension of my Saviour into heaven, or His presence in His church on earth. Where he promises abundance of wealth, honor, and long life, I have changed some of these typical blessings for grace, glory, and life eternal, which are brought to light in the Gospel, and promised in the New Testament. ”[6]
The Bible shows that when the Lord returns, the kingdom of the heavens will come to earth to reign and rule over the earth. The Lord Jesus will establish His kingdom on earth and rule the earth for one thousand years. Christians who leave everything to follow the Lord and who are good, faithful, long-suffering, and overcoming will reign with the Lord Jesus during this one thousand year period. They will sit in glory on thrones together with the Lord to reign and enter into the joy of the Lord in the kingdom.
I love this hymn very much. Anytime I sing this song, it makes me feel at home with my Father, Jehovah God.!!! ( Blessed be to His Holy Name.!!! ) Amen in Jesus Christ's Mighty Name.!!!