Phillipians simply states that God is at work in us for His good pleasure. Therefore we need to consider this in the lives we live. It doesn't state anywhere that men can refuse God's graces.
That's the second part. But what about "work out your salvation with fear and trembling"? Who is told to do that? By the very command to do it, it is implied that we can refuse it. The Scripture does tell us more clearly in other places that we can resist or reject God's graces:
We then, as workers together with Him also plead with you not to receive the grace of God in vain. For He says: "In an acceptable time I have heard you, And in the day of salvation I have helped you." 2 Cor 6:1-2
And who can forget the parable of the sower and the seed in Matthew 13. This parable shows the interaction between God's graces and our nature and response to Him. Without the seed (grace), there can be NO life (in Christ), nothing worthy of eternal life. However, note the seed falls on 4 different soils - each indicative of men's response to the Word. Note the seed that falls on rocky ground... In any case, it is clear from Phil 2:12-13 that their is an interaction between God and man - and in other places, Scripture shows men refusing God's graces.
We are temples of the living God (1 Cor 3:16).
It doesn't say we are permanently so. Read the next verse - we can grieve the Holy Spirit by doing evil, or by willful sin.
"if any man defile the temple of God, him shall God destroy; for the temple of God is holy, which [temple] ye are. 1 Cor 3:17
Pretty clear that men CAN and DO fall away, after becoming Temples of the Holy Spirit...
Regards