Two Ways of Life
The Psalms are divided into 5 divisions or books  This psalm begins the first book and is the first of all the psalms. Therefore, it sets the tone for the whole. 
The Blessed Life (vs. 1-3)
The Hebrew word used here is used very frequently in the Psalms. It basically means happy, blessed is he who… But unlike salvation, which is free, being blessed is costly to the believer. It demands (negatively)
· separation from ungodly, sinful, and scornful people. And (positively)
· commitment to the word of God.
This implies more than just coming to the Assembly to hear a message or two, but absolute delight in studying and meditating on God’s word daily. The result will be a life of fruitfulness, vitality, and prosperity in the midst of a very wicked world.
The Ungodly Life (vs. 4-6)
The ungodly [wicked] are mentioned four times in this Psalm. But, in stark contrast to the righteous, they are headed only for judgment. Though, in this life, the wicked may “prosper” materially, their success will be short-lived. God’s judgment will eventually bring about their destruction. This is because YAHWEH takes care of [“knows”] the righteous but the way of the ungodly will “perish”.
 The divisions are: 1-41; 42-72; 73-89; 90-106; 107-150.
 It is very possible that this Psalm was written by King David. For 37 of the 41 Psalms in Book 1 of the Psalter (Psalms 1-41) are explicitly stated to have been written by him [Cf. Ps. 3, 4, 5, 6, etc]. Also Psalm 2 is said to have been written by David [in Acts 4:25]. Thus it is very probable that all of Book 1 was written by David.
 אַשְׁרֵי asheri
 It is used 29 times in the Psalms and only 20 places elsewhere in the Old Testament.
 The corresponding Greek word μακάριος makarios is used quite often in the New Testament [e.g. Matt. 5:3-11; John 13:17; Matt. 24: 46; Rev. 16:15, 22:14]. It is usually associated with eternal rewards [including ruling with Christ in His kingdom] in its use in the New Testament. See also Ps. 2:12.
 John 4:10, Eph. 2:8-9, Rev. 22:17.
 Vs. 1. This, however, does not mean that we have no contact with such people [Cf. Matt. 10:16; John 17:13-19, Phil. 2:14-16], but rather that we are not listening to their counsel, following in their ways, or imitating their scornful arrogance [1 John 2:16, Titus 1:10-16, 2 Cor. 6:14-18]. Certainly, it is possible for believers to do all of the above [Ezek. 18:24, Dan. 9:15, Jer. 14:20, Neh. 9:33 (where the word רשׁע rasha ungodly is used); 1 Cor. 3:1-4, 6:7ff, Rev. 2:18-29].
 Vs. 2. The word תּוֹרָה torah simply means instruction, teaching. To be blessed of the Lord, we need to know the instruction of the Lord. This is especially emphasized in the Psalms where this word is found over 35 times [Cf. Ps. 19:8 ff and Ps. 119:1ff]. Note the contrast to verse 1 in the following scriptures: counsel Ps. 119:24, way of sinners Ps. 119:63, 15, seat of the scornful Ps. 119:23, 51.
 The word חֵפֶץ (ḥēpeṣ) delight is used of delight of a man for a woman (Gen. 39:19, Esther 2:14) or for various other things (2 Sam 24:3, Esther 6:6).
 Vs. 2. See also Josh 1:8, Ps. 119:14, 15, 16, 23, 24, 35, 47, 48 etc. In the New Testament note Matt. 7:24-27, John 14:21-24, Col. 3:16, Rev 3:20.
 Vs. 3. The image here is of a palm tree flourishing in the desert because it has been planted by [artificial] streams of water in a very dry place [Cf. Ps. 92:12-14]. The “rivers of water” are an image of the word of God. [A similar image is found in Jeremiah 17:5-13.] The fruit [or results] of such a life are mentioned in Psalm 119 [Cf. Ps. 119: 3, 9, 11, 25, 42, etc.]. Further, such a person will constantly be full of life [leaf (foliage) will not fall off]. This life is often needed in the midst of our difficulties and temptations [Cf. Ps. 119:25, 37, 40, 93 etc. See also John 15:4-8]. Further, he will experience success in his work [all that he does shall prosper]. This is illustrated by Gen. 39:2, 3, 23; Josh. 1:8 (Cf. Prov. 28:13). This would indicate spiritual prosperity always (Cf. 3 John 2) and sometimes financial prosperity. [This term צלח tsaleach is almost never used for material prosperity.]
 This is the Hebrew word רָשָׁע rasha mentioned in verses 1, 4, 5, 6. It basically means guilty, wicked person. [Note these references in Psalm 119: 53, 61, 95, 110, 119, 155.]
 Nelson’s New Illustrated Bible Dictionary has this comment: “In the Bible, chaff symbolizes worthless, evil, or wicked persons (or things) that are about to be destroyed (Ps. 1:4; Matt. 3:12; Luke 3:17). It is a fitting figure of speech to describe complete destruction by judgment.”
 Cf. Ps. 73:3, 12.
 Ps. 73:17ff. This, of course, is spoken of in verses 4-6.
 Vs. 6. This is especially in focus during the Tribulation Period where God will establish the congregation of the righteous [Cf. Jer. 30:20, Ps. 99:4, Isa 26:2, 60:21, Amos 9:10]. This same type of judgment is mentioned in Num. 14:26-38, 16:33ff; Matt. 13: 43, 49; 25:31-46, Heb. 12:22-24.
 The Hebrew word ידע yada = know is quite often used in the sense of take care of [Cf. Gen. 39:6, Ps.
31:7; also note Psalm 146:9].
 Vs. 6. It is worthy of note, however, that this word is also used of regenerate people who suffer loss at the Judgment-Seat of Christ [Matt. 16:24-27, 2 John 8; Cf. 1 Cor. 3:12-15].