'Careful to Observe' in the Bible

Be careful to observe the Sabbath day just as the Lord your God has commanded you.

Furthermore, remember that you were a slave in Egypt, and so be careful to observe these statutes.

and then you are careful to observe all these commandments I am giving you today (namely, to love the Lord your God and to always walk in his ways), then you must add three more cities to these three.

"If you indeed obey the Lord your God and are careful to observe all his commandments I am giving you today, the Lord your God will elevate you above all the nations of the earth.