(2) While they behold . . .--The same curious word as in 1Peter 2:12, and the tense, which is ill-represented by "while they behold," sets us at the moment of the triumph of the wife's conduct, literally; having kept, or when they have kept an eye on your chaste conversation. The husband is jealously on the watch to see what his wife does who has embraced these foolish notions; at last he breaks down. Jesus must be the Messiah, or his wife could not have been so chaste! The adjective "chaste" is here to be taken in a large sense; it is the same which enters into the verb translated "purify" in 1Peter 1:22, and it is implied that the "fear" (i.e., of the husband; comp. Note on 1Peter 2:18) has been an incentive to this sweet virtue; "your life so immaculate in fear," or even almost "so timidly pure." Leighton says, "It is a delicate, timorous grace, afraid of the least air, or shadow of anything that hath but a resemblance of wronging it, in carriage or speech, or apparel, as follows in the third and fourth verses."

Verse 2. - While they behold (see note on 1 Peter 2:12, where the same verb occurs) your chaste conversation coupled with fear; literally, your chaste behavior, in fear. Bengel and others understand the fear of God. Certainly the holy fear of God is the sphere in which true Christians must always live. But the close connection with the word "chaste (τὴν ἐν φόβῳ ἁγνὴν ἀναστροφὴν ὑμῶν), and the parallel passage, Ephesians 5:33 (in the Greek), make it probable that the fear here inculcated is reverence for the husband - an anxious avoidance of anything that might even seem to interfere with his conjugal rights and authority.

Matthew Henry's Concise Commentary

3:1-7 The wife must discharge her duty to her own husband, though he obey not the word. We daily see how narrowly evil men watch the ways and lives of professors of religion. Putting on of apparel is not forbidden, but vanity and costliness in ornament. Religious people should take care that all their behaviour answers to their profession. But how few know the right measure and bounds of those two necessaries of life, food and raiment! Unless poverty is our carver, and cuts us short, there is scarcely any one who does not desire something beyond what is good for us. Far more are beholden to the lowliness of their state, than the lowliness of their mind; and many will not be so bounded, but lavish their time and money upon trifles. The apostle directs Christian females to put on something not corruptible, that beautifies the soul, even the graces of God's Holy Spirit. A true Christian's chief care lies in right ordering his own spirit. This will do more to fix the affections, and excite the esteem of a husband, than studied ornaments or fashionable apparel, attended by a froward and quarrelsome temper. Christians ought to do their duty to one another, from a willing mind, and in obedience to the command of God. Wives should be subject to their husbands, not from dread and amazement, but from desire to do well, and please God. The husband's duty to the wife implies giving due respect unto her, and maintaining her authority, protecting her, and placing trust in her. They are heirs together of all the blessings of this life and that which is to come, and should live peaceably one with another. Prayer sweetens their converse. And it is not enough that they pray with the family, but husband and wife together by themselves, and with their children. Those who are acquainted with prayer, find such unspeakable sweetness in it, that they will not be hindered therein. That you may pray much, live holily; and that you may live holily, be much in prayer.

Gill's Exposition of the Entire Bible

While they behold your chaste conversation,.... Cheerful subjection, strong affection, and inviolable attachment to them, and strict regard to the honour of the marriage state, and to the preserving of the bed undefiled with lusts and adulteries:

coupled with fear; with reverence of their husbands, giving them due honour, and showing all proper respect; or with the fear of God, which being before their eyes, and upon their hearts, engages them to such an agreeable conversation.

OpenBible.com