"For I want you to know how great is the contest in which I am engaged for you and those in Laodicea, and all who have not seen me face to face, that their hearts may be encouraged as they are united in love, with a view to [their gaining] all the wealth of fullness of understanding -- namely, the knowledge of the mystery of God, that is, Christ, in whom all the treasures of wisdom and knowledge are concealed."
It seems pretty clear that the contest mentioned here is between Christ and human traditions and the elemental spirits of the world that are mentioned in 2:8. This was alluded to earlier in the letter and twice later. In what way is Paul engaging in this struggle/contest? In 4:12, Epaphras work/struggle takes the form of prayer and this is likely part of what Paul is referring to here in 2:1.
The importance of holding firm to the faith, or perseverance, was a central theme to chapter one and it surfaces again here. Whereas in chapter one the danger of the failure to persevere was highlighted, in chapter two the benefit of succeeding in perseverance is made known. While failing to hold firm to the faith could jeopardize their status as a persons reconciled with and blameless before God (chapter one), a failure to continue on further in that faith by perfecting their unity in love could cause them to miss out on all the benefits (wealth) of being in Christ such as understanding, knowledge, and wisdom which are highly prized here.
While I've scoffed at the two-tier system of Pentecostal Christians who seem to believe that there are Christians and then there are baptized-in-the-holy-spirit Christians, they just might be onto something. And that is that being saved initially is not enough. For Paul, holding firm to that salvation once obtained isn't even enough. We are called to advance continually toward the knowledge, wisdom, and understanding of Christ that comes with a continually increasing unity in brotherly love.
Not all Christians will stand equally before God as if God looks merely at Christ's righteousness and not at all at our own deeds. This is the unequivocal witness of the New Testament, despite being the target of much evangelical preaching in the 20th century. Chrysostom, in his homily to his saved parishioners on Colossians, warns them,
"For don't think that you truly and already have all things. These are hidden also even from angels, not from you only; so that you ought to ask all things from him."
The position of the Christian is lifelong reliance on the continued mercy of God in assurance of his faithfulness to those who put their faith in him and his grace to those who have not yet done so. And while salvation is certainly a result of the Christian life, it is more of a beginning than an end.