Psalm 135:6, "Whatever Yahweh pleased, that he has done, in heaven and in earth, in the seas and in all deeps;" is a powerful declaration of God's absolute sovereignty and control over all creation. Let's break down what that means:

"Whatever Yahweh pleased...": This emphasizes that God's actions are determined by his own will and purpose. He is not subject to any external forces or limitations. His decisions stem from his own wisdom, love, justice, and goodness.

"...that he has done...": This affirms that God's will is always accomplished. His plans are not thwarted or frustrated. It speaks to his omnipotence and his ability to bring about what he intends.

"...in heaven and in earth, in the seas and in all deeps;": This phrase encompasses all of creation. It indicates that God's sovereignty extends to every realm – the celestial realm, the earthly realm, the oceans, and even the deepest parts of the sea (symbolizing the unknown or chaotic). Nothing is outside of his control or influence.

In summary, this verse means:

God is sovereign: He is the ultimate ruler and has the authority to do as he pleases.
God is omnipotent: He has the power to accomplish his will.
God's control is universal: His sovereignty extends over all of creation, both visible and invisible.

Theological Implications:

Comfort and Assurance: The verse offers comfort to believers, knowing that even in the midst of chaos or uncertainty, God is in control.
Humility and Reverence: It encourages humility and reverence towards God, acknowledging his supreme authority and wisdom.
Trust and Faith: It fosters trust and faith in God, believing that he is working out his good purposes in all things, even when we don't understand them.

In essence, Psalm 135:6 is a powerful statement of God's absolute authority and power over all of creation. It is a reminder that he is the ultimate source of all things and that his will is always done.