So, I was raised in a fairly extreme and very hypocritical Christian household. I've been an Atheist for a long time, basically since I left after high school, but this only works if you view sin as only a positive act, a thing you do.
The way I was raised?
Not doing certain things can be just as sinful as doing certain things. Oh, you failed to sufficiently respect your parents? There's a commandment for that. Oh, you failed to prevent your sibling from doing something really stupid (even though you actually told him not to)? Failed to be your brother's keeper, etc.
Regarding laziness/sleep, specifically?
1st Timothy 5:8
Anyone who does not provide for their relatives, and especially for their own household, has denied the faith and is worse than an unbeliever.
Proverbs 10:5
He who gathers crops in summer is a prudent son, but he who sleeps during harvest is a disgraceful son.
2nd Thessalonians 3:6,10
In the name of the Lord Jesus Christ, we command you, brothers and sisters, to keep away from every believer who is idle and disruptive and does not live according to the teaching you received from us. ... For even when we were with you, we gave you this rule: “The one who is unwilling to work shall not eat.”
Again, I don't believe in any of this, but there are plenty, plenty of Christians and Pastors who will pick a few verses willy nilly, as I have just done, and design a whole sermon around them.
Point being: You can quite easily use the Bible to define sleeping all day as being sinful.
