We fill our spiritual lives with all sorts of talk, mostly about how we should be more like Jesus. Typically this includes various items like praying more, giving more, not having bad thoughts, etc. I wonder how much of our spiritual growth follows the instruction of Polycarp here. He is calling believers to be imitators of God's patience, enduring suffering for his glory and following the example of Christ.
How is our kingdom-work affected by our impatience? If we are unwilling to trust in the providence of God's time, we will most certainly fail in living the very nature of the kingdom that of which we are a part. That is to say, failure to wait upon the Lord for strength is to rely on one's own strength which, by definition, is worthless. True faith begins with the willingness to wait upon the Lord - a stance which is not characterized as passive, but which operates in the context of God's eternal presence.
Scripture beckons us to wait upon the Lord for strength, for salvation, for life. It is the path to an uplifting from the mire of corruption, sin and earth. And here, the early Christian writer believes that this patience - this waiting upon the Lord - is imitation of God himself. Perhaps we have missed one of the fundamental aspects of the quiet, insomuch as it brings our noisy fallenness closer to the calm of the divine presence in order that we might connect with him.
Still, I remember the apostle: "The Lord is not slow in keeping his promise, as some understand slowness. Instead he is patient with you, not wanting anyone to perish, but everyone to come to repentance" (2 Peter 3:9). That reads a bit differently now.