Whatever your hand finds to do, do it with [all] your might; for there is no work, nor device, nor knowledge, nor wisdom, in the grave, where you are [eventually] going. — Whatever you do, do it with all your heart, as to the Lord, and not to man; knowing that from the Lord you shall receive the reward of the inheritance: for you are serving the Lord Christ. — Whatever good thing anyone does, he shall receive the same from the Lord.
I must work the works of him who sent me, while it is day: the night comes, when nobody can work.
Brethren, give diligence to make your calling and election sure: for if you do these things, you shall never fall. Don't be lazy; instead be followers of those who through faith and patience inherit the promises.
Be steadfast, unmoveable, always abounding in the work of the Lord, since as you know your labor is not in vain in the Lord.
It's a marvelous thing about the Christian's life that nothing is ever wasted. Not one good thing you do, not one prayer you offer, not one effort to be a better man or woman. It takes determination to "stay the course" as a Christian, but you have the promise of God that He will honor your efforts. He never fails to notice. The corollary is that you must supply effort and determination as a servant of the Lord, and you must always do your best. A fervent, passionate spirit is a wonderful thing if it's directed in the right way, as is the determination to serve God with all your might whatever you are doing--if you are a teacher, then teach, knowing that HE is in the classroom. If you are a mechanic, then let Him guide your daily work. If you are a businessman or woman, you are in business with Him, and He is the senior partner. It's common to distinguish between "ministry" and "work," and call "work" what we do "in the world," and designate it as unimportant or somehow "less." Nothing could be further from the truth. Our lives are a whole, not parts, and the part that is work or family can be just as distinctively Christian as a the part that is "ministry." In fact, your life is ONE. There is no real distinction between one part and another. Your children are your ministry. Your work is your ministry. You can earn a fortune and be God's man, or live in poverty and be the devil's. It's all got to do with who your partner is. Make God your partner in all you do, and then do everything with all your heart.