To start, we should understand that "the word of the Lord" and similar constructs in OT Scripture, has several meanings. These include:
- A communication from God to a prophet or patriarch
- The agency of God's creation
- God's teaching to human beings as expressed in the Law and other scriptures
In the case of Ps. 119:105, the context of the Psalm itself is the best guide to the meaning of the term. The are numerous references to God's word in this Psalm. Here is a representative sampling:
9 How can a young man keep his way pure?
By guarding it according to thy word.
10 With my whole heart I seek thee;
let me not wander from thy commandments!
11 I have laid up thy word in my heart,
that I might not sin against thee.
12 Blessed be thou, O Lord;
teach me thy statutes!..
43 ...And take not the word of truth utterly out of my mouth,
for my hope is in thy ordinances.
44 I will keep thy law continually,
for ever and ever.
66 Teach me good judgment and knowledge,
for I believe in thy commandments.
67 Before I was afflicted I went astray;
but now I keep thy word.
105 Thy word is a lamp to my feet
and a light to my path.
106 I have sworn an oath and confirmed it,
to observe thy righteous ordinances.
160 The sum of thy word is truth;
and every one of thy righteous ordinances endures for ever.
170 Let my supplication come before thee;
deliver me according to thy word.
171 My lips will pour forth praise
that thou dost teach me thy statutes.
Reading these excerpts, it seems obvious that the term "God's word" is meant primarily in the third sense above: as God's teaching to humans, expressed in the Torah Law. God's word is repeatedly related to his "commandments," "ordinances" and "statutes." It is in this sense that the writer says:
Thy word is a lamp to my feet
and a light to my path.
I have sworn an oath and confirmed it,
to observe thy righteous ordinances.
Since God's word is also the agent of creation we may certainly interpret the passage as relating to that agency, whether it is understood as Torah, Logos or Christ. But if we look at it in the immediate context and in the sense of the psalm as a whole, the meaning of "God's word" here is his Torah, his "righteous ordinances," which serve to light the psalmist's way.