The clear knowledge of heaven was not available in the Old Testament. The Promised Land was a physical picture of heaven. Justification is pictured in the sacrificial system of the nation of Israel.
Sanctification is pictured in the holiness laws of the nation of Israel.
Although God was his father he would not have had the knowledge of it. Not motivated by the Holy Spirit to take the Gospel to the world During the Old Covenant era you do not find any clear teaching on evangelism, or the taking of the gospel to the world. The reason for this is found in the purpose of the nation of Israel. Israel was a picture of the true people of God. The gift of hammering was a physical picture of the spiritual gifts of the new covenant era.