IshPs 42(18) :ܥܠ ܙܒܢܐ ܕܚܡܫܥܣܪ ܫ̈ܢܝܢ ܕܐܬܬܘܣܦ ܥܠ ܚܝ̈ܘܗܝ ܕܚܙܩܝܐ ܐܡܪܗ݀ ܡܓܠܝܝܐܝܬ/ܡܓܠܝܢܐܝܬ/‏ : clearly it spoke about the period of 15 years added to Hezekiah's lifetime
See the entire entry for mgalləyānāˀīṯ adv. manifestly, clearly