Charles H. Spurgeon on Psalms 115:9

O Israel, trust thou in the LORD. Whatever others do, let the elect of heaven keep fast to the God who chose them. Jehovah is the God of Jacob, let his children prove their loyalty to their God by their confidence in him. Whatever our trouble may be, and however fierce the blasphemous language of our enemies, let us not fear nor falter, but confidently rest in him who is able to vindicate his own honour, and protect his own servants. He is their help and their shield. He is the friend of his servants, both actively and passively, giving them both aid in labour and defence in danger. In the use of the pronoun "their, "the Psalmist may have spoken to himself, in a sort of soliloquy: he had given the exhortation, "trust in Jehovah, "and then he whispers to himself, "They may well do so, for he is at all times the strength and security of his servants."