Psalm 115 contrasts idols with the living God, Yahweh (often shortened to "Yah"). The surrounding verses highlight the lifelessness of idols, which cannot speak, see, or hear. In contrast, Yahweh is the source of all life and blessing.

Verse 17 states, "The dead do not praise Yah, nor do any who go down into silence." This sets the stage for verse 18.

Meaning of Psalm 115:18: "But we will bless Yah, from this time forward and forever more. Praise Yah!"

"But we will bless Yah..." This is a declaration of the living. Unlike the dead who are silent, the living choose to actively bless and praise God. "Bless" in this context means to speak well of God, to acknowledge His goodness and power, and to offer thanks and adoration.
"...from this time forward..." This signifies a commitment to ongoing praise. It's not just a momentary expression, but a deliberate decision to make praise a continuous part of their lives.
"...and forever more." This extends the commitment of praise beyond the present life into eternity. The praise of God is seen as a perpetual and unending activity.
"Praise Yah!" This is a final exclamation of praise. It is a concise and direct command and expression of worship. It is a concluding affirmation and a call to others to join in the praise of Yahweh.

In essence, the verse means:

Those who are alive will continuously and eternally praise Yahweh (God). This is a conscious choice in contrast to the silence of the dead and the inability of idols to praise. It is a commitment to bless God through words and actions, both now and forever.

Key takeaways:

Living praise: It emphasizes the importance of the living praising God.
Eternal commitment: It highlights a commitment to praise that extends beyond this life.
Contrast with idols: It contrasts the active praise of the living God with the silence of idols.
Affirmation of faith: It serves as a strong declaration of faith in and devotion to Yahweh.