Psalm 1:2

כִּ֤י אִ֥ם בְּתוֹרַ֥ת יְהוָ֗ה חֶ֫פְצ֥וֹ וּֽבְתוֹרָת֥וֹ יֶהְגֶּ֗ה יוֹמָ֥ם וָלָֽיְלָה׃

Translation: But in the law of the Lord is his delight and in the law of the Lord he meditates day and night.

(כִּ֤י אִ֥ם) following a negative clause is a strong adversative, like Greek (ἀλλά), which the Septuagint uses here. The blessed man delights in the law of the Lord. In vs 1, the man does not follow the wicked due to the fact that he is blessed. Here, the man delights in the law of the Lord because he is blessed (see, for example, John 4:32). Anyone who has ever tried to delight in the law of the Lord in order to obtain blessing has discovered what a fruitless exercise it is. The reader should note as well that “law,” while a traditional rendering of (תּוֹרָה), is too narrow. The larger sense of the word is “instruction.” BDB suggests that the use here may refer to the Deuteronomic code, but I think that is unlikely.

(הָגָה) is a poetic word, i.e., it is used only in poetic material. It has the sense of mutter or groan. So the idea here is the conscious meditation on material, perhaps like the half-silent repetition of material to oneself, when one is working on memorizing said material.

( יוֹמָ֥ם וָלָֽיְלָה) is a merismus, the use of two extremes to indicate the whole. So it could be paraphrased “all the time.” It is a shame that most Christians spend so little time meditating on the Word of God.