John Chrysostom

This indeed he brings forward naturally. But this "I will put my trust in Him" (2 Sam. xxii. 3), what does it mean? For what follows this is also introduced naturally. "Behold, I and the children which God hath given Me." (Isa. viii. 18.) For as here He shows Himself a Father, so before, a Brother. "I will declare Thy name unto My brethren," He saith.

Homily on Hebrews 4 ↗

Theophylact of Ohrid

"I will put my trust in Him" — through this He also shows that He became man and our brother. For just as each of men, so He Himself also hopes in Him, that is, in the Father. At the same time He shows us that we should hope in God alone, since He Himself, being the Son and lacking nothing, nevertheless says that He hopes in the Father. …

Commentary on Hebrews ↗

Oecumenius

"I will put my trust in him." Since he previously called Him brother and internally father, he signifies that these indeed are names of kindness and grace, but by nature and truth, God is, he says. For who trusts in anyone else except in God alone? And if he were to say: Do not think that hearing Him being called brother and father refers to someone among the common people, God is, he says, in whom it is written that one must trust. "Here I am, and the children." Here our Father made Christ. …

The Pseudo-Oecumenian Catena on Hebrews ↗

Thomas Aquinas

133. – Then when he says, and again, he shows that Christ Himself depends on the Father by the fact that He says, I will put my trust in him: 'In you, Lord, have I hoped; let me never be confounded' (Ps. 30:2). But he shows the kind of hope He has, namely, firm hope, which is called trust: for hope, even though it is not concerned with the impossible, sometimes has fear joined to it, and then it his properly called hope. But sometimes hope is firm and without fear; then it is called trust. This is the hope Christ had. 134. …

Commentary on Hebrews ↗