IshGen 11:8 :ܟܠ ܟܡܐ ܓܝܪ ܕܢܩܬ ܚܝܪܗ ܕܚܘܫܒܢ ܘܢܣܩ ܩܕܡ ܒܪ̈ܝܬܐ ܒܪ ܒܣܬܪܐܝܬ ܪ̈ܒܘ ܪ̈ܒܘܢ ܫܢ̈ܝܢ‏ : however many myriads of myriads of years we fix our mind's eyes and go back before creation
See the entire entry for barbestrāˀīṯ adv. backwards