The sermon continues an exposition of Paul's prayer for the Ephesians, picking up at Ephesians 3:17b after having covered 16-17a the previous week. The preacher opens with a personal illustration: having just returned from a ministry trip to Indonesia and arriving in a cold Melbourne, he lost his voice yet still had to preach four times in a single day and twice more the next. Rather than fading, his voice grew stronger the more he spoke, an experience he connects to Paul's own testimony that God's power is made perfect in weakness — "when I am weak, then I am strong." This becomes the bridge into the text: Paul prays that the Ephesians would be strengthened in their inner being, and that strengthening is inseparable from being rooted and grounded in love.

The sermon unpacks the two images Paul uses. "Rooted" evokes a tree: roots grow downward, and the deeper a tree roots, the more it draws nutrients and water, enabling it to grow upward — so being rooted in Christ's love means going deep in order to grow high. "Grounded" (or "founded") evokes a building resting on a foundation, and a foundation's adequacy is measured by breadth and length. Together the two metaphors explain why Paul immediately speaks of the love of Christ in terms of width, length, height, and depth — a kind of three-dimensional shape of the cross that the church is called to grasp.

A central turn in the sermon is the Indonesian word mengenal ("to know" in the relational sense) versus merely tahu ("to know about"). The preacher illustrates this with the difference between knowing facts about a president and truly knowing a person intimately, and invokes J.I. Packer's distinction in Knowing God between knowing God and merely knowing about God. Christianity, he insists, is not a religion but a relationship, and this relational knowing comes only through prayer, meditation on the Word, and obedience — quoting John Calvin that "every true knowledge of God is born out of obedience." Corrie ten Boom's word to her sister in a Nazi prison camp, "there is no pit so deep that God's love is not deeper still," and the preacher's own experience of only truly grasping the hardship of mission trips to Timor Tengah Selatan once he went himself, both reinforce that this love is known experientially, not merely informationally.

The sermon then turns to the depth of that love through the doctrine of substitution and union with Christ. It poses a deliberately unsettling question: how can it be just for an innocent person to die in the place of the guilty? Ordinary justice, and Proverbs 17:15's condemnation of both acquitting the guilty and condemning the righteous, would forbid it even if the innocent party were willing. The answer, the sermon argues, lies entirely in union with Christ: because believers are united to Christ by faith, when Christ bore sin and died, those in him are reckoned to have died with him (2 Corinthians 5:14-15), and his righteousness is credited to them. This is described as double imputation — our guilt reckoned to Christ, his righteousness reckoned to us (2 Corinthians 5:21, Romans 8:32) — the only means by which God can be both just and the justifier of sinners.

Turning to being "filled with all the fullness of God," the preacher uses the vastness of a single drop of water, containing roughly 1.67 sextillion molecules, as a picture of a fullness beyond human comprehension, tying it to God's sovereign word over creation and Christ's command that stilled the storm. This fullness is set within the "golden chain" of Romans 8:29-30 — foreknown, predestined, called, justified, glorified — assuring believers that their present rootedness in love is the beginning of a glorification not yet complete. The sermon closes with practical application: this rootedness produces perseverance against sin (quoting Elyse Fitzpatrick on union with Christ), is experienced concretely within the life of the local church as Christ's body, and overflows into love for others, urging the congregation toward continued prayer, Scripture meditation, and communal worship rather than a merely informational faith.

Bible Verses Used

• Ephesians 3:16-19: The sermon's main text, Paul's prayer that believers be strengthened in their inner being and rooted and grounded in love so as to grasp its width, length, height, and depth.

• 2 Corinthians 12:9-10: Referenced through "when I am weak, then I am strong," framing the preacher's own illness as an experience of God's strength in weakness.

• Romans 8:32: Cited to show the depth of the Father's love in not sparing his own Son but giving him up for us.

• Proverbs 17:15: Used to show that justifying the guilty and condemning the innocent are both an abomination to God, sharpening the puzzle of substitutionary atonement.

• 2 Corinthians 5:21: The basis for the doctrine of double imputation — Christ made sin for us so that we might become the righteousness of God.

• 2 Corinthians 5:14-15: Explains union with Christ — because one died for all, all are reckoned to have died in him.

• Romans 8:29-30: The "golden chain" (foreknown, predestined, called, justified, glorified) situating present rootedness in love within God's larger redemptive plan.

• Genesis 1:9-10 and Mark 4:39: Used together to illustrate God's sovereign fullness and power over creation, from separating the seas to calming the storm.

• Ephesians 1:21-23: Cited to connect the fullness of God experienced by believers to the church as the body and fullness of Christ.