If we prove to be unfaithful [i.e., to our commitment to Christ], He [still] remains faithful [to His word], for He cannot deny Himself. [Note: This verse refers to Christ remaining true to His promise of either accepting or rejecting us. See Matt. 10:32-33].
For we [Christians] have had the good news [about resting with God] preached to us, just as the Israelites [had good news proclaimed to them. See 1:16-19]. But the message they heard did not benefit them, because it was not coupled with faith by those who heard it.
But it is not as if the word of God [i.e., His promise to Israel] has failed [in its fulfillment]. For not all those descended from the Israelites are [truly] Israelites [i.e., God’s people].
We ought to thank God for you always, brothers, since it is proper, because your faith is growing so much and the love that every one of you has for each other is increasing more and more.
But all of us [Christians], with unveiled faces, see the Lord’s splendor reflected, as [though we were] looking in a mirror, and [so] are being transformed into His likeness in ever-increasing splendor. This is [the work] of the Lord, [who is] the Holy Spirit.