Hebrews 4:4

For he spake in a certain place of the seventh day on this wise, And God did rest the seventh day from all his works.

The rest spoken of after God's works is the rest of the seventh day, when God ceased His own work. That seventh day is the Sabbath of God's commandments, the day God would have reverenced. That rest still remains as a promise to be entered. Hence there is warning to fear lest anyone come short of that rest through unbelief, for unbelief kept the Israelites from entering the land. The gospel preached to them profits only when it is mixed with faith.

Israel's wilderness generation repeatedly grieved God, so He swore they would not enter His rest, except for the two who wholly followed Him. Entering that rest requires trusting and submitting to Him alone. The rest is a promised destination reached by following God in obedience. The coming great issue will be over that Sabbath day, with the world and the professedly Protestant churches siding with the man of sin against those who have the light on God's commandments.