Every scripture must be read in light of the Finished Work of Jesus Christ. Christ and Him Crucified, He is the central theme of all Scripture.
First of all, let us point out that a lazy person, a slothful person, makes excuses out of fear, out of getting hurt.
One commentary informed me that this fear, like all other fears, is irrational, since there are no lions in the streets or in the public square of a city.
The principle of First Mention can give us greater insight into this passage.
"Slothful" is first mentioned in the Book of Judges:
"And they said, Arise, that we may go up against them: for we have seen the land, and, behold, it is very good: and are ye still? be not slothful to go, and to enter to possess the land." (Judges 18: 9)
Just as in Proverbs 26: 13, it is fear which causes people to be slothful.
This fear is based on unbelief, for unbelief prevented the Israelites from entering the Promised Land the first time:
"Let us therefore fear, lest, a promise being left us of entering into his rest, any of you should seem to come short of it." (Hebrews 4: 1)
"9There remaineth therefore a rest to the people of God. 10For he that is entered into his rest, he also hath ceased from his own works, as God did from his. 11Let us labour therefore to enter into that rest, lest any man fall after the same example of unbelief." (Hebrews 4: 9-11)
This passage refers to the Promised Land, which for every believer today is the Sabbath Rest of Jesus Christ living in us because by His death and resurrection on the Cross, He put away our sins and gave us His righteous standing.
Jesus Christ is our Sabbath Rest:
The original Greek reads: "And I will rest you." He gives us Himself, and through Him we have this rest.
Rest is more than physical rest, but the rest from trying to earn God's grace and righteousness and peace in our lives. We do not work for our salvation, but receive it by grace through faith in Jesus Christ.
In fact, the one work that Jesus wants us to do is to believe on Him:
"Jesus answered and said unto them, This is the work of God, that ye believe on him whom he hath sent." (John 6: 29)
Sloth is a result of unbelief, that we do not believe that Jesus Christ has saved us from death and wishes to bless us all the more.