There's an interesting start/finish scenario in Paul's Second Letter to the Corinthians. It's generally accepted that one of the reasons Paul wrote to them a second time involved his mission to provide an offering for the persecuted and therefore needy believers in Jerusalem. It is a central theme of at least chapter 8 and 9 of the second epistle. Two sections of these chapters are significant in thinking about the life tension that put us humans on a starting line that is never finished.
Accordingly, we urged Titus that as he had started, so he should complete among
you this act of grace.
2 Corinthians 8:6, ESV
And in this matter I give my judgment: this benefits you, who a year ago started
not only to do this work but also to desire to do it. So now finish doing it as well,
so that your readiness in desiring it may be matched by your completing it out of
what you have. For if the readiness is there, it is acceptable according to what a
person has, not according to what he does not have.
2 Corinthians 8:10-12, ESV
There's a good bit of debate regarding the identity of Titus in the Corinthian correspondence. Many believe he is the recipient of the Pastoral Epistle that Paul addressed to his well-known New Testament mission companion Titus while others hold that the name is a street name for Timothy, Paul's younger protege. In the instance of the starting/finishing tension his identity isn't really a central consideration. The point here is that Paul was sending Titus to help the Corinthians finish what they had started, that is, the grace of their assistance to the Jerusalem church.
Evidently the Corinthians had started "to do this work" and we also of one spirit in their "desire to do it". There seemed to be what the Apostle called a "readiness" problem. As a result, they delayed for at least a year deliberating what they could give and perhaps easing back somewhat because they thought their gift wouldn't be sufficient for the need of the Jerusalem church. Paul reminded them to finish what they had started and to give what they could. Their gift, however meager, would be acceptable if given in a spirit of desire and readiness.
It's a very typical start/finish tension. How often we are moved and motivated to be a part of something without actually weighing the cost. Just as often when we do put pencil and paper to the process our contribution may seem small and reflect negatively on our initial desire to participate in the first place. In Paul's words, this tension is the reality collision of wanting to do it, desire, and having the means to do it, readiness. In some instances this tension results in delay---standing at the starting line saying, "ready, set, set, set..." and never pushing the "go" button.
Counting the cost is also a biblical theme. Jesus told parables about taking measure of our commitments before we make them. In this way, our desire to be involved in something meaningful and purposeful can be matched by our readiness to do it, which seems to be Paul's intention here. In real life today this tension can exist out of funding decisions, time commitments, following the crowd, or being involved for a number of wrong reasons.
Paul concluded this section of his letter with two of the most profound promises of Scripture. He reminded them that "God loves a cheerful giver" (9:7), and that "God is able to make all grace abound to you, so that having sufficiency in all things at all times, you may abound in every good work" (9:8). He wanted them to give what they could and rely on God for what they needed.
Finishing what we start requires two things of us. First, to match our desire to start with a readiness to do so. Second, to remember God's promises so that we can finally say, "go".