It occurred to me last night that man has no cause to boast, even if he does fulfill the original Great Commission to fill the earth and subdue it, because the idea does not originate with man.
Mankind was commanded to "be fruitful and multiply and fill the earth and subdue it," in Genesis 1.28. I have a friend who looks at this as the original Great Commission (the second being what Jesus Christ commanded us in Matthew 28.19). Whatever the case, the idea originates with God and therefore also returns to Him because it must.
Man has no cause to boast of anything under the sun because nothing comes from or returns to man. It all comes from and returns to God. Man does not choose the place and time and circumstances of his birth or death, therefore again, man has nothing about which he may boast.
A man cannot do anything to influence his own birth, but he may try to usurp authority from God and choose to take his own life. But what profit is that to anyone? And still, man acknowledges the Holder of all authority even as he attempts to usurp it, because from Whom indeed does man attempt to take the authority of the place and time and method of his own demise? This too, as the teacher says in Ecclesiastes, is vanity, and again I say: man has no cause to boast.
The best a man can do under the sun is to sojourn for a time, for his appointed and predestined time, and pray he comes out unspotted in the end. And this is impossible utterly, except in Christ.