Psalm 149:5 expresses a call for God's faithful followers ("saints") to celebrate and express their joy and praise. Let's break down the meaning of each phrase:

"Let the saints rejoice in honor": This speaks to the idea that the faithful (saints) should be proud of their relationship with God and celebrate His goodness. "Honor" could refer to the glory and dignity God bestows upon them, or the honor they give to God. It suggests a rejoicing that stems from the recognition of their valued status and their role in God's plan. The "saints" are those set apart for God, those who are faithful and dedicated to Him.

"Let them sing for joy on their beds": This part is a bit more nuanced.
The phrase "sing for joy" is a straightforward call to express happiness and gratitude through song.
"On their beds" is interpreted in several ways:
Even in rest: It suggests that their joy shouldn't be confined to formal worship settings. Even in the privacy of their homes, even when resting, their hearts should be filled with joy and praise. It implies a constant, unwavering devotion.
Despite suffering: Some believe it means that even in times of illness or hardship (when confined to bed), the faithful should maintain their joy and praise God. Their faith provides comfort and strength even in difficult circumstances.
Personal and intimate worship: The bed represents a place of intimacy and privacy. Singing on their beds suggests a personal and heartfelt connection with God. It's not just public worship, but a private and sincere expression of love.

In essence, Psalm 149:5 encourages believers to find joy in their relationship with God, to celebrate His honor, and to express that joy through singing and praise, not just in formal settings but even in their most private moments. It's a call to a constant and unwavering devotion and a testament to the power of faith to bring joy even in difficult circumstances.