Psalm 38 is an interesting one, because its overall theme is of feeling chastened by the Lord. To be ‘chastened’ means to be corrected by going through suffering. The speaker does not rail against God at all; he understands the purpose God must have in needing to correct him and bring him to task. He declares his own wrongness and his wretchedness. His trust in the Lord is sure and strong, and we get the sense that he fully understands that all this is the Lord’s way of salvation for him. The opening and closing verses talk about the Lord urgently and with conviction.

Spiritually, this psalm describes our need to understand and accept our frail and broken human nature. By "accepting" I don't mean being satisfied with our spiritual state, or resigned to it. We need even to be practising repentance daily in some way (see The New Jerusalem 163). Repentance involves examining ourselves and seeing our true state and bringing ourselves to the Lord for his aid, protection and illumination. This is an ongoing need. We keep learning to understand more about how the Lord works with us and how we are to manage our spiritual states.

This psalm also describes the Lord’s own deep temptations during his human life. Verses 1 to 10 describe these temptations, such as, “My wounds are foul and festering because of my foolishness” (verse 5). Verses 11 and 12 speak of even those ‘friends’ and ‘companions’ who love good and truth turning from the Lord, wanting his death. Verses 13 and 14 tell us that the Lord bears all this with patience, and verses 15 to 22 (and also verse 9) are about the Lord’s confidence that the hells will not prevail against him.

The psalm begins with the plea not to be punished by the Lord’s anger or his wrath. During our temptations, this is the appearance, yet it is essential that we appreciate that the Lord never punishes but only seek to save us. The Lord’s ‘anger’ is his resolve to free us from evils; the Lord’s ‘wrath’ is his determination to free us from false beliefs. (Arcana Caelestia 3614)

‘Arrows pierce me deeply’ means the way in which the Lord’s truths penetrate our spirit, speaking to it and challenging it and often bringing us pain. (Arcana Caelestia 2686).

The Lord’s hand ‘presses me down’ stands for the Lord’s opposition to our evils (not to us!) because ‘hands’ represent Divine power. (Heaven and Hell 232).

The speaker uses the various organs in our body to describe our various spiritual ailments: flesh, bones, head, wounds, loins, heart and eyes… quite a comprehensive list. ‘Bones’ stand for the truths which support our spiritual frame; ‘loins’ stand for our spiritual loves but also our passions. Each of these organs is defective in the psalm. (Arcana Caelestia 8364)

Verses 11 and 12 talk about the aloofness of friends and relatives, and the deceit of those who want to destroy. Spiritually, this describes the influences that come into our minds during temptation. The heavenly influence seems far off and unable to help us, the hellish influences seem close and condemning. (Arcana Caelestia 9348)

This is immediately followed by words talking about not hearing and not speaking out. In a general way, spiritually, this stands for us not being swayed by the influences – the “voices” – which come into our thought, whatever kind these may be, because we cannot determine their true quality. In a more specific way, it means the refusal to judge and condemn others for their actions. This would be most true of the Lord. (Apocalypse Explained 409)

Then comes the real reason and purpose for us during every temptation, that we are to put our trust in the Lord who hears and knows everything. Only this can be our full confidence.

The final two verses of the psalm are worded as a prayerful request to not be forsaken and to be helped by the Lord. The meaning is right on the surface here. We need to ask the Lord for help, and we also need to understand that the Lord never forsakes us or is unwilling to help.

Here's an extract from Swedenborg's explanation of the inner meaning of the Book of Revelation, in which he has collected a nice set of passages from the Word, about peace. It's powerful to read them as a set.

This is from Apocalypse Revealed 306:

"[In the Word,] Peace symbolizes everything whatever that comes from the Lord, and so everything pertaining to heaven and the church, and the blessings of life in them. In the highest or inmost sense, these are blessings of peace.

It follows from this that peace means charity, spiritual security, and inner rest, for when a person abides in the Lord, he is at peace with his neighbor, which is a state of charity, and he has protection from hell, which is spiritual security. And when he is at peace with his neighbor and has protection from hell, he enjoys an inner rest from evils and falsities.

Accordingly, since all these blessings come from the Lord, it can be seen what is symbolically meant by peace in general and in particular in the following passages:

...unto us a Child is born, unto us a Son is given; the government will be upon His shoulder. His name will be called... God, Hero, Everlasting Father, Prince of Peace. Of the increase of His government and peace there will be no end... (Isaiah 9:6-7)

(Jesus said,) "Peace I leave with you, My peace I give to you." (John 14:27)

(Jesus said,) "These things I have spoken to you, that in Me you may have peace." (John 16:33)

In His days the righteous shall flourish, and much peace... (Psalms 72:3, 7)

Then I will make a covenant of peace... (Ezekiel 34:25, 27; 37:25-26)

How delightful upon the mountains are the feet of him who brings good news, who proclaims peace..., who says to Zion, "Your King reigns!" (Isaiah 52:7)

Jehovah bless you and... lift up His countenance upon you, and give you peace. (Numbers 6:24-26)

Jehovah will bless His people with peace. (Psalms 29:11)

(Jehovah) will redeem my soul in peace... (Psalms 55:18)

The work of (Jehovah) is peace, [and] the labor of righteousness, rest and security forever, that (they) may dwell in a tabernacle of peace, in secure tents, and in tranquil places of rest. (Isaiah 32:17-18)

(Jesus said to the seventy that He sent out,) "Whatever house you enter, first say, 'Peace to this house.' And if a son of peace is there, your peace will rest on it." (Luke 10:5-6, cf. Matthew 10:12-14)

The wretched shall possess the earth, and shall delight themselves in an abundance of peace... ...observe the upright man, for the final state for that man is peace. (Psalms 37:11, 37)

(Zacharias, prophesying, said,) ."..the Dayspring from on high has appeared..., to guide our feet into the way of peace." (Luke 1:78-79)

Depart from evil and do good; seek peace and pursue it. (Psalms 34:14)

Much peace have those who love Your law... (Psalms 119:165)

"Oh, that you had heeded My commandments! Then your peace would have been like a river...." "There is no peace," says Jehovah, "for the impious." (Isaiah 48:18, 22)

(Jehovah) will speak peace to His people... Righteousness and peace will kiss. (Psalms 85:8, 10)

There is no peace in my bones because of my sin. (Psalms 38:3)

He has filled me with bitterness... ...moved (is) my soul far from peace; I have forgotten goodness. (Lamentations 3:15, 17)

And so on in many other places, from which it can be seen that the aforesaid blessings are meant by peace. Fix your mind on spiritual peace, and you will clearly see.

So likewise in the following places: Isaiah 26:12; 53:5; 54:10, 13; Jeremiah 33:6, 9; Haggai 2:9; Zechariah 8:16, 19; Psalms 4:6-8; 120:6-7; 122:6-9; 128:5-6; 147:14."